REPRODUCTION QUICK QUIZ FORM THREE

-
1. What is the significance of reproduction. (2m)2 

2. Distinguish between sexual and asexual reproduction. (2m)4
Sexual
Asexual 

3. (a) What is crossing over. (1m)5
(b)What is its significance. (1m)6
(c) Name two organs in humans where crossing over takes place. (2m)8 

4. A chromosome is a long thread like structure made up of long molecules of DNA wrapped around proteins.
(a)DNA is an abbreviation. What’s the long form of DNA. (1m)9
(b) What is the name the proteins in the above excerpt. (1m)10

5. Distinguish between the following terminologies.(2m)12
(i)Haploid
(ii)Diploid

6. (a)State and explain four ways by which flowering plants prevent self pollination and promote cross pollination. (8m)20
(i)
(ii)
(iii)
(iv)
(b) What is the advantage of cross pollination over self pollination. (2m)22

7. Distinguish between: (8m)30
(a) Apocarpous and syncarpous flowers.
(b) Complete and incomplete flower.
(c) Regular and irregular flower.
(d) Superior and inferior ovary.
THE END

1.      What is the significance of reproduction. (2m)2
-Propagation of a species
-Variation hence improvement of a species. 

2. Distinguish between sexual and asexual reproduction. (2m)4
Sexual
-Involves fusion of gametes Asexual
-No fusion of gametes
3. (a) What is crossing over. (1m)5
-Exchange of genetic material between non-sister chromatids of homologous chromosomes
(b)What is it’s significance. (1m)6
-Is a source of variation (c) Name two organs in humans where crossing over takes place. (2m)8
-Ovary
-Testis

4. A chromosome is a long thread like structure made up of long molecules of DNA wrapped around proteins.
(a)DNA is an abbreviation. What’s the long form of DNA. (1m)9
-Deoxyribonucleic Acid (b) What is the name the proteins in the above excerpt. (1m)10
-Histones
5. Distinguish between the following terminologies.(2m)12
(i)Haploid
-Having a single set of chromosomes (ii)Diploid
-Having two sets of chromosomes.
6. (a)State and explain four ways by which flowering plants prevent self pollination and promote cross pollination. (8m)20
(i) Protandry; Stamens mature before pistils of the same flower/plant making self pollination impossible
(ii) Protogyny; Pistils mature before stamens of the same flower/plant hence self pollination is impossible.
(iii) Dioecism; Male and female reproductive organs are on separate plants of the same species making self pollination virtually impossible.
(iv) Heterostyly; A condition of having unequal styles and filaments among flowers in a cluster thus increasing chances of cross pollination.
NB: Any other relevant answer.

(b) What is the advantage of cross pollination over self pollination. (2m)22
-Mixing of genetic material between the different plants of the same species leading to variation hence improvement of a species.

7. Distinguish between: (8m)30
(a) Apocarpous and syncarpous flowers.
-Apocarpous: Carpels are free/not joined/United. Owtte
-Syncarpous: Carpels are fused.
(b) Complete and incomplete flower.
-Complete: Having all the four floral parts.
-Incomplete: Missing one or more of the four floral parts.
(c) Regular and irregular flower.
-Regular: Having radial symmetry
-Irregular: Having bilateral symmetry
(d) Superior and inferior ovary.
-Superior: Floral parts of a flower are attached at a point below the position of the ovary.
-Inferior:Floral parts of a flower are attached at a point above the position of the ovary
THE END

Comments

Post a Comment

Popular posts from this blog

(a) Define digestion. [2 m] (b) Describe the digestion of a piece of ugali in a human digestive system from the mouth until its assimilation. [18mks]

-
(a) Define digestion It is break down of complex insoluble; v food substance into simple soluble food substances; v 2max (b) Describe the digestion of ugali; Digestion of ugali begins in the mouth;v ugali is chewed by the teeth to increase large surface areav for action of salivary amylase / ptyalin; vThe food mixes with saliva produced by salivary glands;v Saliva contains mucus and enzyme ptyalin. Mucus moistens, softens and lubricates the food;v ptyalin speeds up the conversion of starch to maltose;v ugali is made into bolus in the mouth;v The bolus moves along the oesophagus and prestalsis / by contraction and relaxation of circular and longitudinal muscles into the stomach;v The digestion continues until ugali become acidic since the stomach does not contain carbohydrase / carbohydrate digesting enzymes no digestion of ugali takes place here.v Ugali now...
Read more

Explain how structures of the human ear are adapted to their functions. (20 marks)

-
Image
The pinna;- is funnel shaped to trap sound waves; cartilaginous to maintain the funnel shape; collects and directs sound waves into the external auditory meatus ear; The external auditory canal; - a tube connected to the pinna that directs sound waves from the pinna to the eardrum lining the auditory canal; has hair that trap foreign particles; The canal contains wax-secreting cells; and hair which traps dust particles; and pathogenic bacteria hence prevent them from getting into the ear; The eardrum; - has a thin tough membrane; that easily vibrates when hit by sound waves; transferring them into vibrations. The ear ossiscles; - they act like a layer and they easily move forward and backward to amplify sound vibrations that hit them; The suspensory ligaments; - suspends the ear ossicles and prevents excessive vibration that would otherwise damage the inner parts of the ear; The eustachian tube - it connects the middle ear with the pharynx; and it equalises air pressure between...
Read more

EXPLAIN HOW ABIOTIC FACTORS AFFECT PLANTS. (20MKS)

-
 Explain how abiotic factors affect plants. (20mks) Abiotic factors. Wind; -On a windy day rate of transpiration increases since wind carries away water vapour leaving surrounding of leaves with low humidity; the lower the humidity the more the space in the atmosphere for water molecules to occupy. - Wind disperse fruits, seeds and spore; - Wind is an agent of pollination. - Strong winds break branches of trees and may even uproot some trees; Temperature; -Enzymes work best at optimum temperature; changes in temperature hence influence rate of photosynthesis/respiration; and other enzyme controlled biological reactions. -In aquatic environment temperature affects the percent of dissolved gases. Light; - green plants need light for photosynthesis; - some plants need light for flowering; photoperiodism; - some seeds (lettuce) require light for germination; - light affects opening and closing of stomata; which affects transpiration; gaseous exchange and photosynthesi...
Read more