CLASSIFICATION I:Binomial Nomenclature
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Kingdoms
Living organisms are classified into five kingdoms namely;
Kingdom Fungi
Kingdom Monera (Prokaryota)
Kingdom Protoctista
Kingdom Plantae
Kingdom Animalia
External Features of Organisms
In plants we should look for:-
SPECIFIC OBJECTIVES
By the end of the topic, the learner should be able to:
TOPIC / SUB-TOPIC BREAKDOWN
THE CELL
Introduction
The microscope
The microscope is used to magnify objects.
Magnification
Microscope parts and their functions
To View the Object
Care of a Microscope
Cell Structure as Seen Through the Light Microscope
The cell as seen above has the following:
Cell membrane (Plasma membrane):
Cytoplasm:
Vacuole:
Cell wall:
Chloroplasts;
The Electron Microscope (EM)
Cell Structure as Seen Through Electron MicroscopeThe Plasma Membrane
The Endoplasmic Reticulum (ER)
The Ribosomes
Golgi Bodies
Mitochondria
Lysosomes
The Nucleus
The Chloroplasts
Comparison between animal cell and plant cell
Cell Specialization
Cells are specialized to perform different functions in both plants and animals.
Example;
Animal Tissues
Examples of animal tissues;
Plant Tissues
Example of plant tissues;
Organs
Organ systems
Organism
Practical Activities
Observation and Identification of parts of a light microscope and their functions
Preparation and Observation of Temporary Slides of Plant Cells
Observation of permanent slides of animal cells
Observation and Estimation of Cell Size and Calculation of Magnification of Plant Cells.
These are fats and oils.
Fats are solid at room temperature while oils are liquid. They are made up of carbon, oxygen and hydrogen atoms. The structural units of lipids are fatty acids and glycerol. Fatty acids are made up of hydrocarbon chain molecules with a carboxyl group (-COOH) at one end. In the synthesis of a lipid, three fatty acid molecules combine with one glycerol molecule to form a triglyceride. Three molecules of water are lost in the process. This is a condensation reaction and water is given off. Lipids are hydrolysed e.g. during digestion to fatty acids and glycerol, water is added. Condensation = Glycerol + 3 Fatty hydrolysis Lipid + Water acids
Properties of Lipids
Proteins
Essential and Non-Essential Amino Acids
Formation of Proteins
Functions of Proteins
As structural materials proteins-
As functional chemical compounds. Examples are hormones and enzymes that act as regulators in the body. Respiratory pigments. Examples are haemoglobin that transports oxygen in the blood and myoglobin that stores up oxygen in muscles. Contractile proteins - make up muscles, i.e. myosin and actin. Proteins combine with other chemical groups to form important substances e.g. mucin in saliva. Source of energy. Proteins are a source of energy in extreme conditions when carbohydrates and fats are not available e.g. in starvation.
Enzymes
Properties of Enzymes
Naming of enzymes
Enzymes are named by adding the suffix -ase to: Name of substrate that they work on e.g.
Factors Affecting Enzyme Action
Temperature
TOPICS
Lesson Objectives
By the end of the topic, the learner should be able to:
Meaning of cell physiology
The term physiology refers to the functions that occur in living organisms.
Cell physiology refers to the process through which substances move across the cell membrane. Several physiological processes take place inside the cell e.g. respiration. Oxygen and glucose required enter the cell while carbon (IV) oxide and water produced leave the cell through the cell membrane. Structure and properties of cell membrane
Properties of cell membrane
Permeability
Concentration Gradient
An increase in the concentration of molecules at one region results in a steeper concentration gradient which in turn increases the rate of diffusion. Temperature High temperature increases kinetic energy of molecules. They move faster hence resulting in an increase in rate of diffusion, and vice versa. Size of Molecules or Ions The smaller the size of molecules or ions, the faster their movement hence higher rate of diffusion. Density The denser the molecules or ions diffusing, the slower the rate of diffusion, and vice versa. Medium The medium through which diffusion occurs also affects diffusion of molecules or ions. For example, diffusion of molecules through gas and liquid media is faster than through a solid medium. Distance This refers to the thickness or thinness of surface across which diffusion occurs. Rate of diffusion is faster when the distance is small i.e., thin surface. Surface Area to Volume Ratio The larger the surface area to volume ratio, the faster the rate of diffusion. For example, in small organisms such as Amoeba the surface area to volume ratio, is greater hence faster diffusion than in larger organisms. Factors Affecting DiffusionRole of Diffusion in Living Organisms
Some processes that depend on diffusion include the following:
Osmosis
Factors Affecting Osmosis
Size of solute molecules-
Osmosis' occurs only when solute molecules are too large to pass through a semi-permeable membrane. Concentration Gradient. Osmosis occurs when two solutions of unequal solute concentration are separated by a semi-permeable membrane. Temperature. High temperatures increase movement of water molecules hence influence osmosis. However, too high temperatures denature proteins in cell membrane and osmosis stops. Pressure Increase in pressure affects movement of water molecules. As pressure increases inside a plant cell, osmosis decreases. Roles of Osmosis in Living Organisms
The following processes depend on osmosis in living organisms:
Water Relations in Plant and Animal Cells
Osmotic Pressure
Plasmolysis
Wilting
Water Relations in Plants and AnimalsHaemolysis
Crenation
Active Transport
Factors Affecting Active Transport:
Temperature
Availability of carbohydrates
Metabolic poisons
Role of Active Transport in Living Organisms
Processes requiring active transport:
Practical Activities
1. Experiment to Demonstrate Diffusion
4. Experiment to Demonstrate Turgor and Plasmolysis in Onion Epidermal Cells
CELL PHYSIOLOGY QUESTIONS
1. 1994 Q6 P1
Give a reason for each of the following a) A mature plant cell does not lose its shape even after losing water. b) Xylem vessels do not collapse even when they do not contain water. 2. 1995 Q4 P1 Explain what would happen to red blood cells if they are placed in a concentrated salt solution ( 2 marks) 3. 1995 Q10 P1 An experiment was carried out to investigate the rate of reaction shown below Sucrose →Fructose + Glucose For the products fructose and glucose to be formed, it was found that substance K was to be added and the temperature maintained at 370C. When another substance L was added, the reaction slowed down and eventually stopped. (a) Suggest the identify of substances K and L (2 marks) (b) Other than temperature state three ways by which the rate of reaction could be increased (3 marks) (c) Explain how substance L slowed down the reaction (2 marks) 4. 2000 Q8 P1 Why is oxygen important in the process of active transport in cells? 5. 2004 Q16 P1 a) What is diffusion (2 marks) b) How do the following factors affect the rate of diffusion? i) Diffusion gradient (1 mark) ii) Surface area volume ratio (1mark) iii) Temperature (1mark) c) Outline three roles of active transport in the human body (3 marks) 6. 2005 Q7 P1 State the importance of osmosis in plants. (3 marks) 7. 2009 Q13 P1 (a) Distinguish between diffusion and active transport (2 marks) (b) State one role that is played by osmosis in (1 mark) (i) Plants (ii) Animals 8. 2010 Q7 P1 Distinguish between haemolysis and plasmolysis. (2 marks) FORM 1 BIOLOGY RESOURCES
BIOLOGY TEXTBOOKS 2017/2018 FORM 1
EAST AFRICAN EDUCATIONAL PUBLISHERS Certificate Biology Form 1 ~ Kshs. 458 FOCUS - HIGHFLYER Secondary K.C.S.E Revision Biology ~ Kshs. 465 JOMO KENYATTA FOUNDATION - JYOTI BUNDU - KLB Secondary Biology Book 1 ~ Kshs. 638 LONGHORN Longhorn Secondary Biology Form 1 ~ Kshs. 550 LONGMAN OVERSEAS - LONGMAN KENYA Explore Biology Form 1 ~ Kshs. 618 MALIMU PUBLICATIONS KCSE Revision Series Q & A ~ Kshs. 360 MENTOR PUBLICATIONS - MORAN PUBLISHERS KCSE Golden Tips Revision Series Biology ~ Kshs. 765 Secondary Breakthrough Series Biology Form 1 ~ Kshs. 539 MOTIVATING EDUCATIONAL How to Pass Biology Form 1 & 2 ~ Kshs. 522 MOUNTAIN TOP PUBLISHERS - OXFORD UNIVERSITY PRESS Comprehensive Secondary Biology Form 1 ~ Kshs. 603 Test it & Fix it KCSE Revision Series ~ Kshs. 810 PEZI Principles of Biology Vol.1 3rd Edition ~ Kshs. 590 GOLDEN BELL - SPOTLIGHT PUBLISHERS Spotlight Quick Revision Biology F1 & 2 ~ Kshs. 700 KCSE Mirror Series Biology ~ Kshs. 910 TARGETER PRINTING PRESS - MARIMBA PUBLISHERS LTD - Introduction to Biology NotesTOPIC OBJECTIVES
By the end of the topic, the learner should be able to:
Topics
INTRODUCTION (5 LESSONS)
Introduction to Biology
Biology derived from Greek words
Biology is therefore the study of living things/organisms. Branches of Biology
Importance of Biology
Characteristics of Living Things
Life defined through observations of activities carried out by living things;
Nutrition Nutrition is the processes by which food/nutrients are acquired/made and utilized by living organisms. Green plants and certain bacteria make their own food. All other organisms feed on complex organic materials. Respiration This is the breakdown of food to provide energy. The energy released is used for various activities in the organism. Gaseous Exchange Process through which respiratory gases (CO2 & O2) are taken in and out through a respiratory surface. Excretion Excretion is the removal of metabolic wastes from the body. Substances like urea, carbon dioxide (Carbon (IV) oxide). These substances are poisonous if allowed to accumulate in the body. Growth and Development Growth means irreversible change in size. All organisms increase in size that is, they grow. Development is irreversible change in complexity. As they do so, they also become differentiated in form. Reproduction Reproduction is the formation of new individuals of a species to ensure continued existence of a species and growth of its population. Irritability The ability of organisms to detect and respond to changes in the environment. This is of great survival value to the organism. Movement This the progressive change in position from one place to another. Some organisms are sessile (i.e. fixed to the substratum). The majority of plants move only certain parts. Collection and Observation of Organisms
Biology as a practical subject is learnt through humane handling of organisms.
Materials needed for collection of organisms include:-
Observation of Organisms
Presenting the Results of Observations
Organisms are observed and important features noted down: colour, texture hard or soft; if hairy or not. Size is measured or estimated.
Biological DrawingsIt is necessary to draw some of the organisms. In making a biological drawing, magnification (enlargement) is noted. Indicate the magnification of your drawing, i.e. how many times the drawing is larger/smaller than the actual specimen MG=length of drawing/length specimen How to Draw
Collection, Observation and Recording of Organisms
Collection
Plants and animals collected from the environment, near school or within school compound using nets, bottles and gloves. Animals collected include:- arthropods, earthworms and small vertebrates like lizards/chameleons/ rodents. Place in polythene bags and take to the laboratory. Stinging/poisonous insects killed using ether. Other animals are observed live and returned to their natural habitat. Plant specimen collected include: - leaves, flowers and whole plants. Observations are made to show the following:-
The differences between animals and plants collected.
COMPARISON BETWEEN PLANTS AND ANIMALS
Introduction to Biology Questions and AnswersKCSE BIOLOGY NOTES, SCHEMES OF WORK, OBJECTIVES, QUESTIONS AND ANSWERSNUTRITION IN PLANTS AND ANIMALS:
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schemes of work
more mocks/kcse questions & answers
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Heterotrophism
Meaning and Types of Heterotrophism
- This is a mode of nutrition whereby organisms feed on complex organic matter from other plants or animals.
- All animals are heterotrophs.
- Their mode of feeding is also said to be holozoic to distinguish it from other special types of heterotrophic nutrition namely:
- Saprophytism
- Parasitism
- Saprophytism/saprotrophysim- occurs in most fungi and some forms of bacteria.
- Saprophytes feed on dead organic matter and cause its decomposition or decay.
- Parasitism is a mode of feeding whereby one organism called the parasite feeds on or lives in another organism called the host and harms it.
Modes of Feeding in Animals
- Animals have developed various structures to capture and ingest food.
- The type of structures present depend on the method of feeding and the type of food.
- Carnivorous animals feed on whole animals or portions of their flesh.
- Herbivorous animals feed on plant material.
- Omnivorous animals feed on both plants and animal materials.
Feeding in Mammals
- The jaws and teeth of mammals are modified according to the type of food eaten.
- Mammals have different kinds of teeth.
- Each type of teeth has a particular role to play in the feeding process.
Feeding in Mammals
- The jaws and teeth of mammals are modified according to the type of food eaten.
- Mammals have different kinds of teeth.
- Each type of teeth has a particular role to play in the feeding process.
Feeding in Mammals
- The jaws and teeth of mammals are modified according to the type of food eaten.
- Mammals have different kinds of teeth.
- Each type of teeth has a particular role to play in the feeding process.
- This condition is described as heterodont.
- The teeth of reptiles and amphibians are all similar in shape and carry out the same function.
- They are said to be homodont.
Types of Mammalian Teeth
- Mammals have four kinds of teeth.
- The incisors are found at the front of the jaw.
- They are sharp-edged and are used for biting.
- The canines are located at the sides of the jaw.
- They are pointed and are used for tearing and piercing.
- The premolars are next to the canines and the molars are at the back of the jaw.
- Both premolars and molars are used for crushing and grinding.
- Teeth are replaced only once in a lifetime.
- The first set is the milk or deciduous teeth.
- These are replaced by the second set or the permanent teeth.
- Dentition refers to the type of teeth, the number and their arrangement in the jaw.
- A dental formula shows the type and number of teeth in each half of the jaw.
- The number of teeth in half of the upper jaw is represented above a line and those on the lower jaw below the line.
- The first letter of each type of teeth is used in the formula i.e. i = incisors, c = canines, pm = premolars and m = molars.
- The total number is obtained by multiplying by two (for the two halves of each jaw).
Adaptation of Teeth to Feeding
In general, incisors are for cutting, canines for tearing while premolars and molars are for grinding.
However, specific modifications are observed in different mammals as an adaptation to the type of food they eat.
Teeth of Herbivores
In general, incisors are for cutting, canines for tearing while premolars and molars are for grinding.
However, specific modifications are observed in different mammals as an adaptation to the type of food they eat.
Teeth of Herbivores
- Incisors are long and flat with a sharp chisel like edge for cutting.
- The enamel coating is thicker in front than at the back so that as the tooth wears out, a sharp edge is maintained.
- Canines are reduced or absent.
- If absent, the space left is called the diastema.
- The diastema allows the tongue to hold food and push it to the grinding teeth at the back of the mouth.
- These are transversely ridged.
- The ridges on the upper teeth fit into grooves on the lower ones.
- This gives a sideways grinding surface.
- The teeth of herbivores have open roots i.e., wide opening into the pulp cavity.
- This ensures a continued adequate supply of food and oxygen to the tooth.
- In some herbivores, such as rabbits and elephants, the incisors continue to grow throughout life.
Teeth of Carnivores
- Incisors are reduced in size and pointed.
- They are well suited for grasping food and holding prey.
- Canines are long, pointed and curved.
- They are used for piercing and tearing flesh as well as for attack and defence.
- Premolars and molars: In general, they are long and longitudinally ridged to increase surface area for crushing.
- Carnassial Teeth: These are the last premolars on the upper jaw and the first molars on the lower one.
- They are enlarged for cutting flesh.
- They act as a pair of shears.
- They also crush bones.
- The teeth of carnivores have closed roots i.e., only a very small opening of the pulp cavity to allow food and oxygen to keep teeth alive.
- Once broken, no re-growth can take place.
- Incisors have a wide surface for cutting.
- Canines are bluntly pointed for tearing.
- Premolars and molars have cusps for crushing and grinding.
- The premolars have two blunt cusps while the molars have three to four.
Internal Structure of tooth
The tooth consists of two main parts:
Crown: The portion above the gum; it is covered by the enamel.
Root: The portion below the gum; it is covered by the cement.
The tooth has two roots.
Neck: Is the region at the same level with the gum.
Cement: Fixes the tooth firmly to the jaw bone.
Crown: The portion above the gum; it is covered by the enamel.
Root: The portion below the gum; it is covered by the cement.
The tooth has two roots.
Neck: Is the region at the same level with the gum.
- It forms the junction between the crown and the root.
- It is covered by enamel. Incisors and canines have one root only.
- Premolars have one or two roots while molars have two to three roots each.
- Internally, the bulk of the tooth is made up of dentine which consists of living cells and extends to the root.
- It is composed of calcium salts, collagen and water.
- It is harder than bone but wears out with use.
- This is why it is covered by enamel which is the hardest substance in a mammal's body.
Cement: Fixes the tooth firmly to the jaw bone.
Common Dental Diseases
Dental Carries
Dental carries are the holes or cavities that are formed as acid corrodes enamel and eventually the dentine.
Causes
Treatment depends on the extent of the dental caries:
Extraction of Tooth.
Filling
This involves replacing the dentine with amalgam, a mixture of hard elements e.g. silver and tin.
Root Canal Treatment
This involves surgery and reconstruction.
It saves severely damaged teeth.
The nerves in the root canal are surgically severed.
The tooth is cleaned and filled up with amalgam.
Periodontal Diseases
Dental carries are the holes or cavities that are formed as acid corrodes enamel and eventually the dentine.
Causes
- This is caused by bacteria acting on the food left between teeth and on the cusp.
- Acids are formed that eventually corrode the enamel.
- The pulp cavity is eventually reached.
- A lot of pain is experienced then.
- The bacteria then infect the pulp cavity and the whole tooth decays.
Treatment depends on the extent of the dental caries:
Extraction of Tooth.
Filling
This involves replacing the dentine with amalgam, a mixture of hard elements e.g. silver and tin.
Root Canal Treatment
This involves surgery and reconstruction.
It saves severely damaged teeth.
The nerves in the root canal are surgically severed.
The tooth is cleaned and filled up with amalgam.
Periodontal Diseases
- These are diseases of the gum.
- The gum becomes inflamed, and starts bleeding.
- Progression of the disease leads to infection of the fibres in the periodontal membranes and the tooth becomes loose.
- This condition is known as pyorrhoea.
- The diseases are caused by poor cleaning of the teeth.
- The accumulation of food particles leading to formation of plaque, lack of adequate vitamin A and C in the diet.
- Nutrition - by taking adequate balanced diet rich in vitamins A and C.
- Antibiotics are used to kill bacteria.
- Anti-inflammatory drugs are given.
- Antiseptic is prescribed to use in cleaning the mouth daily to prevent further proliferation of bacteria.
- The plaque is removed-drilled away - a procedure known as scaling.
Care of Teeth
In order to maintain healthy teeth the following points should be observed:
- A proper diet that includes calcium and vitamins, particularly vitamin D is essential.
- The diet should also contain very small quantities of fluorine to strengthen the enamel.
- Large quantities of fluorine are harmful.
- The enamel becomes brown, a condition known as dental fluorosis.
- Chewing of hard fibrous foods like carrots and sugar cane to strengthen and cleanse the teeth.
- Proper use of teeth e.g. not using teeth to open bottles and cut thread.
- Regular and thorough brushing of teeth after meals.
- Dental floss can be used to clean between the teeth.
- Not eating sweets and sugary foods between meals.
- Regular visits to the dentist for checkups.
- Washing the mouth with strong salt solution or with any other mouth wash with antiseptic properties.
Digestive System and Digestion in Humans
Organs that are involved with feeding in humans constitute the digestive system.
Digestive System and Associated Glands
Organs that are involved with feeding in humans constitute the digestive system.
Digestive System and Associated Glands
- Human digestive system starts at the mouth and ends at the anus.
- This is the alimentary canal.
- Digestion takes place inside the lumen of the alimentary canal.
- The epithelial wall that faces the lumen has mucus glands (goblet cells).
- These secrete mucus that lubricate food and prevent the wall from being digested by digestive enzymes.
- Present at specific regions are glands that secrete digestive enzymes.
- The liver and pancreas are organs that are closely associated with the alimentary canal.
- Their secretions get into the lumen and assist in digestions.
- Mouth.
- Oesophagus.
- Stomach.
- Small intestines - consist of duodenum, the first part next to the stomach, ileum - the last part that ends up in a vestigial caecum and appendix which are nonfunctional.
- Large intestines consist of: colon and rectum that ends in the anus.
Ingestion, Digestion and Absorption
- Feeding in humans involves the following processes:
- Ingestion: This is the introduction of the food into the mouth.
- Digestion: This is the mechanical and chemical breakdown of the food into simpler, soluble and absorbable units.
- Absorption: Taking into blood the digested products.
- Assimilation: Use of food in body cells.
- Mechanical breakdown of the food takes place with the help of the teeth.
- Chemical digestion involves enzymes.
- In the mouth, both mechanical and chemical digestion takes place.
- Food is mixed with saliva and is broken into smaller particles by the action of teeth.
- Saliva contains the enzyme amylase.
- It also contains water and mucus which lubricate and soften food in order to make swallowing easy.
- Saliva is slightly alkaline and thus provides a suitable pH for amylase to act on cooked starch, changing it to maltose.
- The food is then swallowed in the form of semisolid balls known as boluses.
- Each bolus moves down the oesophagus by a process known as peristalsis.
- Circular and longitudinal muscles along the wall of the alimentary canal contract and relax pushing the food along.
- In the stomach, the food is mixed with gastric juice secreted by gastric glands in the stomach wall.
- Gastric juice contains pepsin, rennin and hydrochloric acid.
- The acid provides a low pH of 1.5-2.0 suitable for the action of pepsin.
- Pepsin breaks down protein into peptides.
- Rennin coagulates the milk protein casein.
- The stomach wall has strong circular and longitudinal muscles whose contraction mixes the food with digestive juices in the stomach.
Digestion in the Duodenum
- In the duodenum the food is mixed with bile and pancreatic juice.
- Bile contains bile salts and bile pigments.
- The salts emulsify fats, thus providing a large surface area for action of lipase.
- Pancreatic juice contains three enzymes:
- Trypsin which breaks down proteins into peptides and amino acids,
- Amylase which breaks down starch into maltose, and
- Lipase which breaks down lipids into fatty acids and glycerol.
- These enzymes act best in an alkaline medium which is provided for by the bile.
- Epithelial cells in ileum secrete intestinal juice, also known as succus entericus.
- This contains enzymes which complete the digestion of protein into amino acids, carbohydrates into monosaccharides and lipids into fatty acids and glycerol.
- This is the diffusion of the products of digestion into the blood of the animal.
- It takes place mainly in the small intestines though alcohol and some glucose are absorbed in the stomach.
- It is highly coiled.
- The coiling ensures that food moves along slowly to allow time for its digestion and absorption.
- It is long to provide a large surface area for absorption.
- The epithelium has many finger-like projections called villi (singular villus).
- They greatly increase the surface area for absorption.
- Villi have microvilli that further increase the surface area for absorption.
- The wall of villi has thin epithelial lining to facilitate fast diffusion of products of digestion.
- Has numerous blood vessels for transport of the end products of digestion.
- Has lacteal vessels; for absorption of fatty acids and glycerol and transport of lipids.
- Glucose and other monosaccharides as well as amino acids are absorbed through the villi epithelium and directly into the blood capillaries.
- First they are carried to the liver through the hepatic portal vein, then taken to all organs via circulatory system.
Absorption of Fatty Acids and Glycerol
- Fatty acids and glycerol diffuse through the epithelial cells of villi and into the lacteal.
- When inside the villi epithelial cells, the fatty acids combine with glycerol to make tiny fat droplets which give the lacteal a milky appearance.
- The lacteals join the main lymph vessel that empties its contents into the bloodstream in the thoracic region.
- Once inside the blood, the lipid droplets are hydrolysed to fatty acids and glycerol.
- Vitamins and mineral salts are absorbed into the blood capillaries in' the villi. Water is mainly absorbed in the colon.
- As a result the undigested food is in a semi-solid form (faeces) when it reaches the rectum.
- Egestion: This is removal of undigested or indigestible material from the body. Faeces are temporarily stored in the rectum then voided through the anus. Opening of the anus is controlled by sphincter muscles
- Assimilation: This is the incorporation of the food into the cells where it is used for various chemical processes.
- Carbohydrates are used to provide energy for the body.
- Excess glucose is converted to glycogen and stored in the liver and muscles.
- Some of the excess carbohydrates are also converted into fat in the liver and stored in the adipose tissue' (fat storage tissue), in the mesenteries and in the connective tissue under the skin, around the heart and other internal organs.
- Amino acids are used to build new cells and repair worn out ones.
- They are also used for the synthesis of protein compounds.
- Excess amino acids are deaminated in the liver.
- Urea is formed from the nitrogen part.
- The remaining carbohydrate portion is used for energy or it is converted to glycogen or fat and stored.
- Fats are primarily stored in the fat storage tissues.
- When carbohydrates intake is low in the body, fats are oxidised to provide energy.
- They are also used as structural materials e.g. phospholipids in cell membrane. They act as cushion, protecting delicate organs like the heart.
- Stored fats under the skin act as heat insulators.
Summary of digestion in humans
Importance of Vitamins, Mineral Salts, Roughage and Water in Human Nutrition
Vitamins
- These are organic compounds that are essential for proper growth, development and functioning of the body.
- Vitamins are required in very small quantities.
- They are not stored and must be included in the diet.
- Vitamins Band C are soluble in water, the rest are soluble in fat.
- Various vitamins are used in different ways.
- Mineral ions are needed in the human body.
- Some are needed in small amounts while others are needed in very small amounts (trace).
- All are vital to human health.
- Nevertheless, their absence results in noticeable malfunction of the body processes.
- Water is a constituent of blood and intercellular fluid.
- It is also a constituent of cytoplasm.
- Water makes up to 60-70% of total fresh weight in humans.
- No life can exist without water.
- Acts as a medium in which chemical reactions in the body takes place.
- Acts as a solvent and it is used to transport materials within the body.
- Acts as a coolant due to its high latent heat of vaporisation.
- Hence, evaporation of sweat lowers body temperature.
- Takes part in chemical reactions i.e. hydrolysis.
Vitamins, sources, uses and the deficiency disease resulting from their absence in diet
Roughage
A diet is balanced when it contains all the body's nutrient requirements and in the right amounts or proportions.
A balanced diet should contain the following:
This is faulty or bad feeding where the intake of either less or more than the required amount of food or total lack of some food components.
Deficiency Diseases
Deficiency diseases result from prolonged absence of certain components in the diet.
Examples are:
Marasmus:
Lack of enough food results in thin arms and legs, severe loss of fluid, general body wasting, sunken eyes.
Kwashiorkor
Lack of protein in the diet of children. The symptoms of kwashiorkor include wasting of the body, red thin hair, swollen abdomen and scaly skin.
Other deficiency diseases are due to lack of accessory food factors (vitamins and mineral salts.). Such diseases include rickets, goitre and anaemia.
Treatment of these deficiency diseases is by supplying the patient with the component missing in the diet.
- Roughage is dietary fibre and it consists mainly of cellulose.
- It adds bulk to the food and provides grip for the gut muscles to enhance peristalsis.
- Roughage does not provide any nutritional value because humans and all animals not produce cellulase enzyme to digest cellulose.
- In herbivores symbiotic bacteria in the gut produce cellulase that digests cellulose.
- Age: Infants, for instance, need a greater proportion of protein than adults.
- Sex: males generally require more carbohydrates than females.
- The requirements of specific nutrients for females depends on the stage of development in the life cycle.
- Adolescent girls require more iron in their diet; expectant and nursing mothers require a lot of proteins and mineral salts.
- State of Health: A sick individual requires more of certain nutrients e.g. proteins, than a healthy one.
- Occupation: An office worker needs less nutrients than a manual worker.
A diet is balanced when it contains all the body's nutrient requirements and in the right amounts or proportions.
A balanced diet should contain the following:
- Carbohydrates
- Proteins
- Lipids
- Vitamins
- Mineral Salts
- Water
- Dietary fibre or roughage
This is faulty or bad feeding where the intake of either less or more than the required amount of food or total lack of some food components.
Deficiency Diseases
Deficiency diseases result from prolonged absence of certain components in the diet.
Examples are:
Marasmus:
Lack of enough food results in thin arms and legs, severe loss of fluid, general body wasting, sunken eyes.
Kwashiorkor
Lack of protein in the diet of children. The symptoms of kwashiorkor include wasting of the body, red thin hair, swollen abdomen and scaly skin.
Other deficiency diseases are due to lack of accessory food factors (vitamins and mineral salts.). Such diseases include rickets, goitre and anaemia.
Treatment of these deficiency diseases is by supplying the patient with the component missing in the diet.
Practical Activities
- Experiments to show that Carbon (IV) Oxide is necessary for Photosynthesis
- Experiment to Show Effect of Light on Photosynthesis
- Experiment to Show the Effect of Chlorophyll on Photosynthesis
- Experiment To Observe Stomata Distribution in Different Leaves
- Test for Reducing Sugar
- Test for non-reducing sugar
- Test for Lipids;
- Test for Proteins -Biuret Test
- Experiment To Investigate Presence of Enzyme in Living Tissue
- Dissection of a Rabbit to show the Digestive System
TOPIC OBJECTIVES
By the end of the topic, the learner should be able to:
- use the magnifying lens to observe the external features of plants and animals
- record observations of the main external characteristics of living organisms, preserved specimens and photographs
- state the necessity and significance of classification
- name the major units of classification
- state the application of Binomial nomenclature in naming organisms.
topics / sub-topics breakdown
- Review the use of magnifying lens
- External features of plants and animals
- Necessity and significance of classification
- Major units of classification: (naming)
- Kingdoms
- Monera
- protoctista
- fungi
- plantae
- animalia (At least one example of each)
- For kingdom plantae and animalia, cover phylum/division, class, order, family, genus and species. Show relationship between the taxonomic units (Give at least one example of each taxon)
- Kingdoms
- Discussion on Binomial nomenclature
- Practical activities
- Use of collecting nets, cutting instruments and hand lens.
- Collection and detailed observation of:
- small animals e.g. insects
- plants - rhizoids, root systems (taproot, fibrous and adventitious), stems and leaves
- Collection and detailed observation of:
Classification I
Introduction
Classification is putting organisms into groups.
Classification is based on the study of external characteristics of organisms.
It involves detailed observation of structure and functions of organisms.
Organisms with similar characteristics are put in one group.
Differences in structure are used to distinguish one group from another.
The magnifying lens is an instrument that assists in the observation of fine structure e.g. hairs by enlarging them.
Classification is putting organisms into groups.
Classification is based on the study of external characteristics of organisms.
It involves detailed observation of structure and functions of organisms.
Organisms with similar characteristics are put in one group.
Differences in structure are used to distinguish one group from another.
The magnifying lens is an instrument that assists in the observation of fine structure e.g. hairs by enlarging them.
Using a Magnifying Lens
A specimen is placed on the bench or held by hand,
Then the magnifying lens is moved towards the eye until the object is dearly focused and an enlarged image is seen.
The magnification can be worked out as follows:
Note: magnification has no units.
Then the magnifying lens is moved towards the eye until the object is dearly focused and an enlarged image is seen.
The magnification can be worked out as follows:
Note: magnification has no units.
Necessity/need for Classification
To be able to identify organisms into their taxonomic groups.
To enable easier and systematic study of organisms.
To show evolutionary relationships in organisms.
To enable easier and systematic study of organisms.
To show evolutionary relationships in organisms.
Major Units of Classification (Taxonomic Groups)
Taxonomy is the study of the characteristics of organisms for the purpose of classifying them.
The groups are Taxa (singular Taxon).
The taxonomic groups include:
The groups are Taxa (singular Taxon).
The taxonomic groups include:
- Species: This is the smallest unit of classification. Organisms of the same species resemble each other. The number of chromosomes in their cells is the same. Members of a species interbreed to produce fertile offspring.
- Genus (plural genera): A genus is made up of a number of species that share several characteristics. Members of a genus cannot interbreed and if they do, the offspring are infertile.
- Family: A family is made up of a number of genera that share several characteristics.
- Order: A number of families with common characteristics make an order.
- Class: Orders that share a number of characteristics make up a class.
- Phylum/Division: A number of classes with similar characteristics make up a phylum (plural phyla) in animals. In plants this is called a division.
- Kingdom: This is made up of several phyla (in animals) or divisions (in plants). It is the largest taxonomic unit in classification.
Kingdoms
Living organisms are classified into five kingdoms namely;
- Monera,
- Protoctista,
- Fungi,
- Plantae
- Animalia.
Kingdom Fungi
Some are unicellular while others are multicellular.
They have no chlorophyll.
Most are saprophytic e.g. yeasts, moulds and mushrooms.
A few are parasitic e.g. Puccinia graminae.
They have no chlorophyll.
Most are saprophytic e.g. yeasts, moulds and mushrooms.
A few are parasitic e.g. Puccinia graminae.
Kingdom Monera (Prokaryota)
These are very small unicellular organisms.
They lack a nuclear membrane
do not have any bound membrane organelles.
Hence the name Prokaryota.
They are mainly bacteria, e.g. Vibrio cholerae.
They lack a nuclear membrane
do not have any bound membrane organelles.
Hence the name Prokaryota.
They are mainly bacteria, e.g. Vibrio cholerae.
Kingdom Protoctista
They are unicellular organisms.
Their nucleus and organelles are surrounded by membranes (eukaryotic).
They include algae, slime moulds - fungi-like and protozoa
Their nucleus and organelles are surrounded by membranes (eukaryotic).
They include algae, slime moulds - fungi-like and protozoa
Kingdom Plantae
They are all multicellular.
They contain chlorophyll and are all autotrophic.
They include; Bryophyta (moss plant), Pteridophyta (ferns) and Spermatophyta (seed bearing plants).
They contain chlorophyll and are all autotrophic.
They include; Bryophyta (moss plant), Pteridophyta (ferns) and Spermatophyta (seed bearing plants).
Kingdom Animalia
These are all multicellular and heterotrophic.
Examples are annelida (earthworms), mollusca (snails),athropoda, chordata .
Example of Arthropods are ticks, butterflies.
Members of Chordata are fish, frogs and humans.
Examples are annelida (earthworms), mollusca (snails),athropoda, chordata .
Example of Arthropods are ticks, butterflies.
Members of Chordata are fish, frogs and humans.
External Features of Organisms
In plants we should look for:-
Spore capsule and rhizoids in moss plants.
Sori and fronds in ferns.
Stem, leaves, roots, flowers, fruits and seeds in plants.
In animals, some important features to look for are:
Segmentation, presence of limbs and, number of body parts, presence and number of antennae. These are found in phylum arthropoda:
Visceral clefts, notochord, nerve tube, fur or hair, scales, fins, mammary glands, feathers and wings.
These are found in chordata.
Spore capsule and rhizoids in moss plants.
Sori and fronds in ferns.
Stem, leaves, roots, flowers, fruits and seeds in plants.
In animals, some important features to look for are:
Segmentation, presence of limbs and, number of body parts, presence and number of antennae. These are found in phylum arthropoda:
Visceral clefts, notochord, nerve tube, fur or hair, scales, fins, mammary glands, feathers and wings.
These are found in chordata.
Binomial Nomenclature
Organisms are known by their local names.
Scientists use scientific names to be able to communicate easily among themselves.
This method of naming uses two names, and is called Binomial nomenclature.
The first name is the name of the genus: (generic name) which starts with a capital letter.
The second name is the name of the species (specific name) which starts with a small letter.
The two names are underlined or written in italics.
Man belongs to the genus Homo, and the species, sapiens.
The scientific name of man is therefore Homo sapiens.
Maize belongs to the genus Zea, and the species mays.
The scientific name of maize is Zea mays.
Scientists use scientific names to be able to communicate easily among themselves.
This method of naming uses two names, and is called Binomial nomenclature.
The first name is the name of the genus: (generic name) which starts with a capital letter.
The second name is the name of the species (specific name) which starts with a small letter.
The two names are underlined or written in italics.
Man belongs to the genus Homo, and the species, sapiens.
The scientific name of man is therefore Homo sapiens.
Maize belongs to the genus Zea, and the species mays.
The scientific name of maize is Zea mays.
Practical Activities
Use of Collecting Nets, Cutting Instruments and Hand Lens.
Forceps are used to collect crawling and slow moving animals.
Sweep nets are used to catch flying insects.
Cutting instrument like scapel is used to cut specimen e.g. making sections.
Hand lens is used to magnify small plants and animals.
Drawing of the magnified organism are made and the linear magnification of each calculated.
Forceps are used to collect crawling and slow moving animals.
Sweep nets are used to catch flying insects.
Cutting instrument like scapel is used to cut specimen e.g. making sections.
Hand lens is used to magnify small plants and animals.
Drawing of the magnified organism are made and the linear magnification of each calculated.
Collection and Detailed Observation of Small Plants and Animals
E.g. moss, ferns, bean.
Look for the following:
Moss plants: Rhizoids and spore capsules.
Fern plants: Rhizomes with adventitious roots; large leaves (fronds) with Sori (clusters of sporangia).
Seed plants: Tree/shrub (woody) or non-woody (herbs) e.g. bean.
Root system - fibrous, adventitious and tap root.
Stem - position and length of internodes.
Type of leaves - simple or compound; arranged as alternate, opposite or whorled.
Flower - colour, number of parts, size and relative position of each:
Fruits - fleshy or dry; edible or not edible.
Seeds - monocotyledonous or dicotyledonous.
Small animals e.g. earthworms, tick, grasshopper, butterfly, beetles.
Observe these animals to see:
Look for the following:
Moss plants: Rhizoids and spore capsules.
Fern plants: Rhizomes with adventitious roots; large leaves (fronds) with Sori (clusters of sporangia).
Seed plants: Tree/shrub (woody) or non-woody (herbs) e.g. bean.
Root system - fibrous, adventitious and tap root.
Stem - position and length of internodes.
Type of leaves - simple or compound; arranged as alternate, opposite or whorled.
Flower - colour, number of parts, size and relative position of each:
Fruits - fleshy or dry; edible or not edible.
Seeds - monocotyledonous or dicotyledonous.
Small animals e.g. earthworms, tick, grasshopper, butterfly, beetles.
Observe these animals to see:
- Number of legs.
- Presence or absence of wings.
- Number of antennae.
- Body covering.
- Body parts.
Taxonomic Groups
Taxonomy is the study of the characteristics of organisms for the purpose of classifying them.
The groups are Taxa (singular Taxon).
The groups are Taxa (singular Taxon).
The taxonomic groups include:
- Species:
This is the smallest unit of classification. Organisms of the same species resemble each other. The number of chromosomes in their cells is the same. Members of a species interbreed to produce fertile offspring. - Genus (plural genera):
A genus is made up of a number of species that share several characteristics. Members of a genus cannot interbreed and if they do, the offspring are infertile. - Family:
A family is made up of a number of genera that share several characteristics. - Order:
A number of families with common characteristics make an order. - Class:
Orders that share a number of characteristics make up a class. - Phylum/Division:
A number of classes with similar characteristics make up a phylum (plural phyla) in animals. In plants this is called a division. - Kingdom:
This is made up of several phyla (in animals) or divisions (in plants). It is the largest taxonomic unit in classification.
Introduction to Classification I. Biology Form 1 Notes
- Classification is putting organisms into groups.
- Classification is based on the study of external characteristics of organisms.
- It involves detailed observation of structure and functions of organisms.
- Organisms with similar characteristics are put in one group.
- Differences in structure are used to distinguish one group from another.
- The magnifying lens is an instrument that assists in the observation of fine structure e.g. hairs by enlarging them.
Classification 1, Topics, Sub-Topics and Other Contents
- Review the use of magnifying lens
- External features of plants and animals
- Necessity and significance of classification
-
Major units of classification: (naming)
- Kingdoms
- Monera
- protoctista
- fungi
- plantae
- animalia (At least one example of each)
- For kingdom plantae and animalia, cover phylum/division, class, order, family, genus and species. Show relationship between the taxonomic units (Give at least one example of each taxon)
- Kingdoms
- Discussion on Binomial nomenclature
- Practical activities
-
Use of collecting nets, cutting instruments and hand lens.
- Collection and detailed observation of:
- small animals e.g. insects
- plants - rhizoids, root systems (taproot, fibrous and adventitious), stems and leaves
- Collection and detailed observation of:
Objectives of Teaching Classification 1
By the end of the topic, the learner should be able to:
- use the magnifying lens to observe the external features of plants and animals
- record observations of the main external characteristics of living organisms, preserved specimens and photographs
- state the necessity and significance of classification
- name the major units of classification
- state the application of Binomial nomenclature in naming organisms.
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