2.DNA has bases A, T, G, C while RNA has A, U, G, C (uracil replaces thymine).
3.DNA is double-stranded, RNA is single-stranded.
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1 (c) (i) List FOUR characteristics of enzymes:
1.They are biological catalysts.
2.They are specific in action.
3.They are protein in nature.
4.They are affected by temperature and pH.
1 (c) (ii) List FOUR evidences of evolution:
1.Fossil records.
2.Comparative anatomy (homologous structures).
3.Comparative embryology.
4.Molecular evidence (DNA/protein similarities).
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2 (a) (i) Define ecological succession.
– A natural, gradual process by which ecosystems change and develop over time, involving replacement of one community by another.
2 (a) (ii) Define food chain.
– A sequence of organisms in which energy is transferred by being eaten or by eating.
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2 (b) State TWO reasons for the choice of garden pea plant by Gregor Mendel for his experiment in genetics:
1.They have clearly distinguishable contrasting traits (e.g. tall/dwarf).
2.They have a short life cycle and produce many offspring.
TYPE B
1 (a) Describe the structure and function of Deoxyribonucleic acid (DNA) as a vital biological molecule in living organisms. [5 Marks]
Structure:
•DNA is a double helix made of two polynucleotide strands.
•Each strand is composed of nucleotides containing a deoxyribose sugar, phosphate group, and nitrogenous base.
•The four bases are adenine (A), thymine (T), guanine (G), and cytosine (C).
•Adenine pairs with thymine (A–T) and guanine pairs with cytosine (G–C) by hydrogen bonding.
•The strands are antiparallel and twisted into a helix.
Function:
•DNA stores genetic information used in the development, functioning, and reproduction of living organisms.
•It directs protein synthesis through transcription and translation.
•DNA ensures inheritance by passing genetic traits from parents to offspring.
•It regulates cellular activities by controlling gene expression.
•It undergoes replication to maintain genetic continuity.
1 (c) (i) State FOUR functions of Protein. [2 Marks]
1.Structural function (e.g. collagen in connective tissues).
2.Enzymatic function (enzymes act as biological catalysts).
3.Transport function (e.g. haemoglobin carries oxygen).
4.Hormonal function (e.g. insulin regulates blood sugar).
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1 (c) (ii) Mention TWO approaches to ecological studies. [1 Mark]
1.Autecology – Study of individual organisms in relation to their environment.
2.Synecology – Study of groups of organisms or communities in relation to their environment.
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2 (a) State SIX characteristics of an Enzyme. [3 Marks]
1.Enzymes are biological catalysts.
2.They are mostly proteins in nature.
3.They are highly specific in action.
4.They speed up reactions without being used up.
5.They are affected by temperature and pH.
6.They lower the activation energy of reactions.
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2 (b) Doctors and insurance companies use graphs to decide if a person has suitable weight for their height. The graph below is an example.
(Since the graph is not shown in your photo, the question will likely ask you to interpret it, e.g., determine if someone is underweight, normal, overweight, or obese based on their height/weight position on the graph).
The general rule:
•Below the normal band → underweight.
•Within the band → healthy/normal weight.
•Above the band → overweight/obese.
TYPE C
BIO 001: GENERAL BIOLOGY
1(a) Copy and Complete the following table
Organelle Function
Ribosome Site of protein synthesis
Mitochondrion Site of cellular respiration and energy (ATP) production
Rough Endoplasmic Reticulum Synthesis and transport of proteins
Golgi apparatus (Body) Packaging of materials such as proteins
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1(b) Define the following areas of Biology
i. Entomology – The branch of biology that deals with the study of insects.
ii. Virology – The study of viruses and virus-like agents, including their structure, classification, and ways to infect and exploit host cells.
iii. Zoology – The scientific study of animals, including their biology, physiology, and classification.
iv. Mycology – The branch of biology that deals with the study of fungi.
v. Histology – The study of the microscopic structure of tissues and cells.
vi. Malacology – The study of mollusks (e.g., snails, clams, squids).
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1(c) Theories of Evolution
i. Darwin’s theory of evolution (Natural Selection):
Organisms with favorable traits survive and reproduce, passing those traits to offspring, leading to gradual changes in species over time.
ii. Lamarck’s theory of evolution (Inheritance of acquired traits):
Organisms develop characteristics during their lifetime due to use or disuse of organs, and these acquired traits are passed on to offspring.
iii. Six evidences in support of organic evolution
1. Fossil records (showing progressive changes in organisms over time).
2. Comparative anatomy (homologous structures indicate common ancestry).
3. Embryology (similar embryonic stages among different organisms).
4. Molecular biology (similarities in DNA, RNA, and proteins across species).
5. Geographical distribution (similar species in different locations suggest common origins).
6. Vestigial organs (structures with no apparent function, e.g., human appendix).
2(a) i. Four differences between Mitosis and Meiosis
Feature Mitosis Meiosis
Number of divisions One cell division Two successive cell divisions
Number of daughter cells Produces 2 daughter cells Produces 4 daughter cells
Chromosome number Maintains diploid (2n) chromosome number Reduces chromosome number to haploid (n)
Genetic variation Produces genetically identical cells Produces genetically different cells
