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BIOLOGY REVISION NOTES FORM 1 TO 4 IN PDF

Maverick John

BIOLOGY FORM 4 REVISION NOTES

  1. a) i) Define the term genetics

iii) List some characteristics which are inherited

 HERE ARE THE NOTES IN PDF;

BIOLOGY FORM FOUR SUMMARIZED NOTES

Biology notes form 1-4 pdf download free

iii) State the importance of genetics

 

  1. b) i) Explain the meaning of the following terms

Heredity

Trait

Gene

Allele

Chromosomes

DNA

  1. ii) List the types of chromosomes
  1. c) i) What is variation?

 

  1. ii) State the causes of variation in organisms

iii) Name the types of variation

  1. iv) Explain the following terms

Acquired characteristics

Inherited characteristics

Genotype

Phenotype

Dominant gene (character)

Recessive gene

Homozygous

Heterozygous

F1 and F2

  1. d) i) Explain Mendels first law of inheritance

 

 

 

 

  1. ii) Give an example of this law

 

iii) What is monohybrid inheritance?

  1. What is complete dominance?

 

  1. e) i) What is meant by co dominance?

 

  1. ii) Give an example of co dominance

In a certain plant species, some individual plants may have only white, red or pink flowers. In an experiment a plant with white flowers was crossed with a parent with red flowers. Show results of F1 generation. Use letter R for red gene and W for white gene.

 

 

 

 

 

 

 

 

 

 

 

 

 

If the plants form F1 were selfed, work out the phenotype ratio for the F2 generation

 

 

 

 

 

 

 

 

 

 

 

 

Phenotypic ratio   1red:2pink:1white

Genotypic ratio 1:2:1

 

 

 

 

  1. f) i) What is a test cross?

– A cross between an individual showing a character for a dominant gene(that is homozygous or heterozygous) with a homozygous recessive individual

OR

  1. ii) State the importance of a test cross in genetics

iii) What are multiple alleles?

 

 

  1. iv) Explain the inheritance of ABO blood groups

 

Give a worked example using parents with heterozygous blood groups AO and BO

 

 

 

 

 

 

 

 

 

  1. Explain the inheritance of Rhesus factor (Rh) in human beings

 

Let the gene for dominant Rh factor be R while gene for recessive be r

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  1. g) i) What does the term linkage mean?

– These are genes which occur together on a chromosome and are passed to offspring without being separated

  1. ii) Define the term sex-linked genes

iii) What is meant by the term sex linkage?

  1. iv) Name the sex-linked traits in humans
  1. v) Give an example of a sex linked trait in humans on:

Y Chromosome

X Chromosome

 

 

 

 

 

 

 

 

 

 

 

 

 

  1. vi) In humans red-green colour blindness is caused by a recessive gene C, which is sex-linked. A normal man married to a carrier woman transmits the trait to his children. Show the possible genotypes of the children.

Let C represent the gene for normal colour vision (dominant)

Let c represent the gene for colour blindness

Parental phenotype Norman man x carrier woman

 

 

 

 

 

 

 

 

 

 

 

  1. State the importance of sex linkage
  1. Haemophilia is due to a recessive gene. The gene is sex-linked and located on the x chromosome. The figure below shows sworn offspring from phenotypically normal parents

 

 

 

 

 

 

What are the parental genotypes?

Work out the genotypes of the offspring

 

 

 

 

 

 

 

 

  1. h) i) What is mutation?

 

 

 

 

 

 

 

 

 

  1. ii) Describe how mutations arise

 

 

iii) State the factors that may cause mutation

Radiations                                                Effects

X-rays                                           gene/chromosome alteration

Ultra violet rays                           structural distortion of DNA

 

Chemicals                                                 Effect

– colchicines                                 prevents spindle formation

Cyclamate                                     chromosome aberrations

Mustard gas                                  chromosomes aberrations

Nitrous acid                                  adenine in DNA is deaminated so behaves like guanine

Acridone orange                           addition and removal of bases of DNA

Formaldehyde

 

  1. iv) State the characteristics of mutations

 

  1. v) Explain chromosomal mutation

– Change in nature, structure or number of chromosomes

 

  1. vi) Explain how the following types of chromosomal mutations occur

 

Duplication

Inversion

Deletion

 

 

 

Translocation

 

Non-disjuntion

Failure of homologous chromosomes/sister chromatids to separate/segregate during meiosis

 

Polyploidy

 

vii) What are gene mutations?

  1. Explain how the following occur during gene mutation

 

Deletion

Inversion

Insertion

Substitution

 

  1. Name the disorders in humans caused by gene mutation

 

  1. State the practical applications of genetics
    1. Breeding programmes (research)

 

 

 

 

 

 

  1. Genetic engineering

– legal questions of paternity knowledge of blood groups or blood transfusion

 

  1. iv) Genetic counseling

 

  1. v) Others

– Pre-sex determination

Understanding human evolution and origin of other species.

 

  1. a) i) Explain the meaning of evolution

 

  1. ii) Differentiate organic evolution from chemical evolution as theories of origin of life

 

iii) What is special creation?

 

  1. b) Discuss the various kinds of evidence for evolution

 

  1. Fossils

 

  1. Comparative anatomy

 

 

 

 

 

 

  1. Comparative serology/physiology

 

  1. Geographical distribution

 

Examples

 

  1. Cell biology (cytology)

 

  1. c) i) State the evolutionary characteristics that adopt human beings to the environment

– Brain

– Eyes

– Upright posture/bipedal locomotion

– prehensible arm/hand

– Speech

 

 

 

 

 

 

  1. ii) State the ways in which Homo sapiens differs from Homo habilis

 

  1. d) i) Explain Larmarck’s theory of evolution
  1. ii) Explain why Lamarck’s theory of evolution is not accepted by biologists today

iii) Explain Darwin’s theory of evolution

  1. e) i) What is natural selection?

– Organisms with certain characteristics are favoured by the environment

Such organisms tend to survive and produce viable offspring

Others not favored are eliminated from subsequent generations

 

  1. ii) With examples, explain how natural selection takes place

 

iii) State the advantages of natural selection to organisms

 

  1. iv) State the ways in which sexual reproduction is important in the evolution of plants and animals

 

 

 

 

 

 

  1. v) Explain the significance of mutation in evolution

– Mutation bring about variation which can be inherited

– Some of these variations are advantageous to the organism

– Others are disadvantageous

– The advantageous variations favour the organism to compete better in the struggle for survival

– This results into a more adapted organism to its environment or new species/varieties

– Those with disadvantageous characters will be discriminated against therefore eliminated from the population/death/perish

 

  1. vi) Plain why it is only mutations in genes of gametes that influence evolution

 

vii) How would you prove that evolution is still taking place?

 

 

  1. f) How has industrial melaninism i.e. peppered moth contributed towards the mechanism of evolution

 

– This is an example of natural selection

– The peppered moth exists in two distinct forms, the speckled white form (normal form) and a melanic form (the black/dark)

– They usually rest on leaves and barks of trees that offer camouflage for protection

– Originally the “speckled white” form predominated the unpolluted area of England

– This colouration offered protection against predatory birds

– Due to industrial pollution tree barks have blackened with soot

– The white form underwent mutation

– A black variety/mutant emerged suddenly by mutation

– It had selective advantage over the white forms that were predated upon in the industrial areas

– The speckled white form is abundant in areas without soot/smoke

 

  1. a) i) Define irritability, stimulus and response irritability

-also called sensitivity

– Responsiveness to change in environment

 

Stimulus

A change in the environment of organism which causes change in organism’s activity

Response

  1. ii) State importance of irritability to living organisms

 

 

 

  1. b) i) What are tactic responses?

 

  1. ii) What causes tactic responses?

 

iii) State the importance of tactic response to:

Members of kingdom protista

Microscopic plants

– escape injurious stimuli/seek favorable habitats

 

  1. Name the type of response exhibited by:

Euglena when they swim towards the source of light

 

  1. State the advantages of tactic responses to organisms

 

  1. c) i) Define the term tropism
  1. ii) Explain the various types of tropism in plants

Phototropism

 

 

 

 

 

 

Geotropism

Thimotropism/Haptotropism

Hydrotropism

chemostropism

iii) State the ways in which tropisms are important to plants

 

 

  1. iv) Explain the differences between tropic and tactic responses
Tropisms Taxes
–        growth curvature in response

–        slow

–        influenced by hormones

 –        locomotory response

–        fast

–        external influence

 

 

 

  1. d) The diagram below represents growing seedlings which were subjected to unilateral light at the beginning of an experiment

 

 

 

 

 

 

 

R

 

 

 

  1. State the results of P, Q and R after 5 days

 

  1. Account for your results in (i) above

P- Growth substance/growth hormone/IAA/auxin are produced by the stem tip

Q- Source of auxin has been removed

R- The auxins cannot be affected by light because the tip has been covered

 

 

  1. State the expected results after 3 day is if the box were removed

 

  1. e) In an experiment to investigate a certain aspect of plant response, a seedling was placed horizontally as shown in diagram I below. After seven days the appearance of the seedling was as shown in diagram 2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Account for the curvature of the shoot and root after the seven days

  1. Shoot
  1. Root

 

 

 

 

 

  1. f) What is etiolation?

 

  1. a) i) What is coordination in animals

– The linking together of all physiological activities that occur in the body so that they take place at the right time and in the correct place

 

  1. ii) Name the main systems for coordination in animals

– Nervous system/sensory system

– Endocrine (hormonal system)

 

iii) List the components of the mammalian sensory system

– Central nervous system (CNS), brain & spinal cord

– Peripheral nervous system (PNS) cranial and spinal nerves

– Sense organs

– Autonomic nervous system (ANS) nerve fibers and ganglia

 

iv).Explain the terms receptors, conductors and effectors

– Receptors are structures that detect stimuli i.e. sense organs

– Conductors transmit impulses from receptors to effectors e.g. neurons

– Effectors are the responding parts e.g. muscles, glands

 

  1. v) What are the functions of the central nervous system?

– provides a fast means of communication between receptors and effectors

– coordinates the activities of the body

 

  1. vi) State the differences between somatic and autonomic systems of peripheral nervous system

– Somatic is concerned with controlling the conscious or voluntary actions of the body i.e. skin, bones, joints and skeletal muscles

– the autonomic (automatic) nervous system controls involuntary actions of internal organs, digestive system, blood vessels, cardiac muscles and glandular products.

 

  1. b) i) What is a neurone?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  1. ii) Name the parts of a typical neurone and state the functions of each part

 

 

 

 

  1. Describe the structure and function of a motor neurone

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  1. Describe the structure and function of sensory neurone

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  1. Describe the structure and function of a relay neurone

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  1. c) State the functions of the major parts of the human brain

 

 

 

 

 

 

 

  1. i) Cerebrum

 

 

 

 

 

 

  1. ii) Mid brain

 

  1. Hind brain

 

  1. i) What is reflex action?

 

 

 

  1. ii) Describe a reflex action that will lead to the withdrawal of a hand from a hot object

 

 

 

 

 

 

 

 

 

 

iii) Explain how an impulse is transmitted across the synapse (gap)

 

  1. Briefly describe the transmission of a nervous impulse across a neuro-muscular junction

 

 

 

 

 

 

 

 

  1. i) What is a conditioned reflex?

 

  1. ii) Explain a conditioned reflex

 

iii) Compare a simple reflex action with a conditioned reflex

 

Simple reflex Conditioned reflex
  • independent of experience
  • one stimulus to evoke response
  • some sensory and motor neurons used
  • reflex is simple
  • dependent on experience
  • both substitute and original reflex evoke response
  • sensory component replaced but motor remains unchanged
  • reflex is modified

 

 

  1. i) What are endocrine glands?

 

  1. ii) State the functions of hormones in animals

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

iii) Name the main endocrine glands, their secretions and functions in the human body

Gland Hormone Functions
Thyroid Thyroxine Increases rate of metabolism
Parathyroid Parathyroid hormone Regulates calcium and phosphate levels
Pituitary Hormone growth Regulate growth of body
  Gonadotrophic hormone Stimulates the development of male and female sex organs
Lactogenic hormone (prolactin) Stimulates secretion of milk after child birth
Thyrotropic hormone(TSH) – proper functioning of thyroid gland/thyroxine production
Adrenocorthicotropic hormone (ACTH) – stimulates release of adrenal cortex hormone
Oxytocin
  • regulates blood pressure
  • stimulates smooth muscles
  • stimulates contraction of uterus during childbirth
  • aids in flow of milk from mammary glands
Follicle stimulating hormone(FSH)
  • causes maturation of egg in females
  • stimulates sperm production in males
Vasopressin (ADH) Antiduretic hormone – regulates water balance by kidneys
Adrenal Adrenaline (epinephrine)
  • for emergency
  • prepares body to cope up with stress
  Aldosterone – maintains balance of salt and water in blood
  Cortisone
  • breaks down stored proteins to amino acids
  • aids in breakdown of adipose tissue
  • regulates sugar level in blood
  • prevents inflammation

 

 

 
  Sex hormones
  • supplements sex hormones produced by gonads
  • promotes development of sexual characteristics
Pancrease Insulin
  • regulates level of sugar in blood
  • enables liver to store sugar
Glucagons
  • regulates level of sugar in blood
Ovaries Oestrogen
  • causes sexual secondary characteristics in females
  • prepares uterus for pregnancy
Progesterone
  • growth of mucus lining of uterus
  • maintains uterus during pregnancy
Testes Androgens(testosterone)
  • causes secondary sexual characteristics in males
Stomach cells Gastrin
  • stimulates release of gastric juice
Intestinal cells Secretin
  • stimulate release of pancreatic juice

 

 

  1. iv) Give the differences between nervous and endocrine (hormonal) communication
Nervous Hormonal (endocrine)
Response confined to effector organs (localized targets) Response more widespread (various targets)
Speed of response is rapid Response less rapid
Nervous impulse thro\\ugh nerves/nerve cell/neurons Hormones transferred through blood
Duration of response is short Persist for long
Speed of transmission is rapid Speed of transmission is slower
Transmission is electrical Transmission is chemical
   

 

 

 

 

 

 

 

  1. v) State the effects of over secretion and under secretion of adrenaline and thyroxine in humans
Hormone Over secretion Under secretion
Adrenaline
  • thin toneless muscles
  • high blood pressure
  • weak bones
  • obesity
  • early onset of sexual development
  • low blood pressure
  • inability to withstand stress
  • fatigue
  • muscular weakness
  • muscle wasting
  • increased dark pigmentation of skin
Thyroxine
  • increased metabolism
  • increased heartbeat
  • physical restlessness
  • mental restlessness
  • protruding eyeballs
  • enlarged thyroid gland
  • cretinism(retarded growth and low mental development
  • lowered metabolism
  • low ventilation rate of lungs
  • low body temperature
  • lowered mental activity
  • coarse hair
  • puffy eyes
  • enlarged thyroid gland

 

 

 

  1. g) i) Define the following terms

Drug

Drug abuse

 

  1. ii) State the types of drugs, examples and side effects

Sedatives

Pain-killers

Hallucinogens

 

 

 

Stimulants

 

iii) State the general effects of drug abuse on human health

 

 

  1. h) i) List the special sense organs in mammals and the major function of each

– Eye for sight

– Ear for hearing and balance

– Nose for smell

– Skin for touch, temperature detection, pain detection

 

 

 

 

 

 

 

 

 

 

 

 

 

iii) What is accommodation of the eye?

 

 

  1. iv) Explain how an eye viewing a near object adjusts to viewing a far object

 

 

  1. v) What changes occur in the eye if it changes from observing an object at a distance to one at a closer range?

– ciliary muscles contract

– Tension in suspensory ligaments reduces/relax/ slackens

– Lens bulges/thickens/increases curvature

– Radial muscles contract

– Circular muscles relax

– Size of pupil becomes large to allow in more light.

 

 

 

 

 

 

 

 

  1. Explain how the eye forms an image

 

  1. Name the defects of the eye and state how they can be corrected

Short sight (Myopia)

 

 

 

 

 

 

 

Long sight (Hypermetropia)

 

 

 

 

 

 

 

Presbyopia

Squinting

 

 

 

 

 

 

 

Astigmatism

 

  1. State the advantages of having two eyes in human beings

 

I i) What are the functions of the human ear?

 

 

  1. How are the structures of the human ear suited to perform the function of hearing?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

iii) Explain how the structure of the human ear performs the function of balancing

 

  1. iv) State what would happen if the auditory nerve was completely damaged

 

 

 

  1. a) i) What is support?

 

 

  1. ii) What is locomotion?

iii) State the importance of support systems in living organisms

  1. iv) State the importance of locomotion in animals

 

  1. b) i) Name the tissues in higher plants that provide mechanical support

 

  1. ii) State the importance of support in plants

 

iii) Name the types of plant stems

 

  1. iv) Name the tissues in plants that are strengthened with lignin

 

  1. v) What makes young herbaceous plants remain upright?

 

  1. vi) State the ways by which plants compensate for lack of ability to move from one place to another

 

 

 

  1. c) i) Explain the ways in which erect posture is maintained in a weak herbaceous stem

– This is the function of turgidity and presence of collencyma

Cells take in water and become turgid

 

 

 

  1. ii) Explain how support in plants is achieved

 

  1. d) i) Give the reasons why support is necessary in animals

 

  1. ii) Why is movement necessary in animals?

 

  1. e) i) Name the organ used for support by animals

– Skeleton

 

  1. ii) Name the different types of skeletons in animals, giving an example of an animal for each type of skeleton named

 

iii) State the difference between exoskeleton and endoskeleton

 

  1. iv) State the advantages of having an exoskeleton

 

  1. v) Explain the importance of having an endoskeleton

 

 

 

  1. f) i) Explain how a fish is adapted to living in water

 

  1. ii) Explain how a finned fish is adapted to locomotion in water

 

  1. g) i) Name the main parts of the vertebral column giving the types of bones found in each part

Axial skeleton

Appendicular skeleton

 

  1. ii) What are the vertebrae?

 

iii) State the functions of the vertebral column

 

 

 

 

 

 

  1. iv) State the general characteristics of vertebrae

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  1. v) Name the bones of the vertebral column

– Cervical vertebra

– Thoracic vertebra

– Lumbar vertebra

– Sacral vertebra

– Caudal vertebra

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  1. vi) Describe how the various vertebrae are adapted to their functions
Bone Structure Function
Skull
  • cranium and jaw bones
  • made of several bones joined together
  • large box called cranium and smaller paired boxes for eyes, ears, nose, jaws
  • has large hole called foramen magnum for the passage of spinal cord
  • attachment of jaws
  • protect brain and other delicate parts
Cervical region

Atlas (first cervical)

 

 

 

 

 

 

 

 

 

 

 
  • ring shaped
  • no Centrum
  • broad, flat transverse processes
  • vertebraterial canal for passage of vertebral artery
  • facet for articulation of condyles of skull
  • protect spinal cord
  • attachment of muscles
  • allow nodding of head
Axis (second cervical)

 

 

 

 

 

 

 

 

 

 

 
  • adontoid peg projects from Centrum
  • large flattened neural spine
  • vertebrasterial canal
  • small transverse process
  • allows head to rotate
  • protects spinal cord
  • provides surface for muscle attachment
Cervical (others)

 

 

 

 

 

 

 

 

 

 
  • short neural spine
  • branched transverse process for neck muscles
  • vertebraterial canals
  • wide neural canal
  • support weight of head
  • protect spinal cord
  • neck muscle attachment
Thoracid

 

 

 

 

 

 

 

 

 

 

 
  • long backward pointing neural spine
  • transverse process that points sideways
  • facets for articulation of ribs
  • notch for spinal nerves to pass through
  • forms rib cage
  • articulation with one end of a rib
  • protects, spinal cord
  • muscle attachment
Lumbar

 

 

 

 

 

 

 

 

 

 
  • short neural spine
  • long transverse process pointing towards abdomen
  • large Centrum
  • extra processes e.g. prezygapophysis, hypapophysis, anapophysis, metapophysis
  • protect organs of abdomen
  • support upper part of body
  • protect spinal cord
  • muscle attachment
Sacral

 

 

 

 

 

 

 

 

 
  • fused bones to form sacrum
  • well developed transverse process of first vertebra
  • vertebraterial canals
  • short neural spine
  • protects alimentary canal
  • attachment of hip girdles
  • protect spinal cord
  • muscle attachment
Rib

 

 

 

 

 

 

 
  • long
  • flattened
  • attached to sternum from front
  • protect internal organs
  • muscle attachment

 

 

 

 

 

 

 

 

 

 

vii) Describe the bones that form the appendicular skeleton

Bone Structure Function
Pectoral girdle scapular (shoulder bone)

 

 

 

 

 

 

 

 
  • Broad i.e. Flattened blade
  • glenoid cavity to articulate with humerus
  • metacromion/acromion for muscle attachment
  • hard to provide support
  • socket with cartilage/smooth surface to reduce friction
 Support

Muscle attachment

Articulates with humerus
Humerus

 

 

 

 

 

 

 

 
  • long shaft for muscle attachment
  • round head to articulate with glenoid cavity
  • trochlea for articulation with ulna
  • olecranon fosa to prevent arm bending the other way
  • movement
  • muscle attachment
Ulna and radius

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
  • ulna longer and on side of little finger
  • has sigmoid notch and olecranon process to form hinge joint with humerus
  • radius is smaller and lies along thumb side and does not join ulna
  • allows articulation with wrist bones
  • movement
  • muscle attachments
Pelvic girdle(hip bone)

 

 

 

 

 
  • composed of three fused bones (ilium, ischium, pubis)
  • upper end fused to sacrum
  • lower end has acetabalum for articulation with femur
  • has abturator foramen for passage of nerves and blood vessels
  • movement
  • muscle attachment
  • support
  • absorbs pressure exerted by ground when animal moves
Femur

 

 

 

 

 

 

 

 

 

 

 

 

 
  • rounded head to fit in acetabulum of pelvis
  • projections called trochanter for attachment of thigh muscles
  • condyles at lower end for articulation with tibi
  • patella that covers knee and prevents leg from bending backwards
  • movement
  • muscle attachment
Tibia and fibula

 

 

 

 

 

 

 
  • tibia is longer than fibula
  • tibia is outer bone and fibula is inner bone
  • tibia lies on side of large toe
  • fibula is fused to tibia (on outer side)
  • movement
  • muscle attachment

 

 

 

 

 

 

 

 

  1. a) What is a joint?

 

  1. ii) State the functions of joints

 

iii) Name the main types of joints

 

  1. iv) Give the features of movable joints

 

  1. b) Describe the synovial joints
  1. Ball and socket

 

 

 

 

 

 

  1. Hinge joint

 

 

 

 

 

 

 

 

 

 

  1. Pivot joint
  1. c) i) What is synovial fluid?

 

 

 

 

  1. ii) State the functions of synovial fluid

 

  1. Explain the following terms
  2. Ligament
  1. Cartilage

 

  1. Muscles
  1. i) What is a muscle?

 

  1. ii) State the functions of muscles

 

  1. Describe the structure and function of various types of muscles
  2. skeletal muscles
  1. Involuntary muscles

 

 

 

  1. Explain how muscles cause movement of the human arm

 

  1. i) State the structural differences between skeletal muscles e.g. biceps and smooth muscles e.g. gut muscle
Skeletal (biceps) Smooth (gut) muscle
  • multinucleated
  • striated/stripped
  • long muscle fibers
  • block/cylindrical
  • uninucleated
  • unstriated
  • short muscle fibers
  • spindle shaped

 

  1. ii) Name the cartilage found between the bones of the vertebral column
  1. What are the functions of the cartilage named in (d) ii) above

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