Introduction

Question 1

What is the hereditary information in all cells?

Answer 1

DNA (Deoxyribonucleic acid)

Question 2

By what mechanism do cells replicate their hereditary information?

Answer 2

Templated polymerisation

Question 3

What is a DNA nucleotide composed of?

Answer 3

Deoxyribose, a phosphate group, a base (A, T, C or G)

Question 4

What is an RNA nucleotide composed of?

Answer 4

Ribose, a phosphate group, a base (A, U, C, or G)

Question 5

What is the intermediary form of hereditary information?

Answer 5

RNA (Ribonucleic acid)

Question 6

How is DNA expressed?

Answer 6

Transcription and translation

Question 7

What type of RNA guides the synthesis of proteins?

Answer 7

mRNA (messenger RNA)

Question 8

What are the specialised chemical properties of RNA?

Answer 8

• it has a flexible backbone so can bend back on itself, which means it can form bonds with itself
• its shape enables it to recognise other molecules by selectively binding to them
• can catalyse chemical changes in certain cases

Question 9

Define a gene

Answer 9

A segment of DNA that corresponds to the production of a protein or functional RNA molecule

Question 10

Define ‘genome’

Answer 10

All of the DNA in a cell, coding and non-coding

Question 11

What are the monomer units of a protein?

Answer 11

Amino acids

Question 12

What are the two processes by which cells reproduce?

Answer 12

Asexual and sexual reproduction

Question 13

What happens in asexual reproduction?

Answer 13

A cell divides to form two identical daughter cells that are clones of the mother cell

Question 14

What happens in sexual reproduction?

Answer 14

Two gametes fuse to form a zygote

Question 15

How does the genetic alphabet change during translation?

Answer 15

The alphabet changes from a four letter alphabet (A, U, G, and C) to an alphabet of 20 amino acids

Question 16

The information in the sequence of a messenger RNA molecule is read out in groups of three nucleotides at a time called ______

Answer 16

codons

Question 17

What are codons?

Answer 17

Nucleotide triplets that code for a specific amino acid

Question 18

What type of molecules read codons?

Answer 18

tRNA (transfer RNA) molecules

Question 19

Define diploid

Answer 19

A cell that contains two copies of each gene

Question 20

Define haploid

Answer 20

A cell that contains only one copy of each gene

Question 21

What multimolecular machines carry out translation?

Answer 21

Ribosomes

Question 22

What comprises a ribosome?

Answer 22

Two main chains of rRNAs (ribosomal RNAs) and more than 50 different proteins

Question 23

What was Gregor Mendel’s experiment?

Answer 23

He bred round seeds (wild-type: RR) and wrinkled seeds (mutant: rr) to produce offspring with the phenotypes Rr. He then self pollinated these plants and found that 1/4 were RR, 1/2 Rr, and 1/4 were rr. The conclusion was that the peas must contain some ‘information’ they pass on.

Question 24

Define allele

Answer 24

An alternate form of a gene found at the same loci in a stretch of DNA

Question 25

Define homozygous

Answer 25

A diploid in which the two alleles of a gene are identical (either AA or aa)

Question 26

Define heterozygous

Answer 26

–A diploid in which the two alleles of a gene are different (Aa)

Question 27

What is a dominant allele?

Answer 27

An allele which always shows its effects on the phenotype if it is present in the genotype

Question 28

What is a recessive allele?

Answer 28

An allele that only shows its effects on the phenotype if the genotype is absent of a dominant allele