DNA

Question 1

Locus

Answer 1

Position of a gene on a strand of DNA.

Question 2

Genes

Answer 2

are short sections of DNA that contain coded information as a specific sequence of bases. Genes code for polypeptides that determine the nature and development of organisms.

Question 3

Mutation

Answer 3

A change in the base sequence of a gene

Question 4

Alleles

Answer 4

alternative forms of a gene (created through mutations).

Question 5

Codon

Answer 5

A sequence of three bases (called a triplet) that codes for a specific amino acid.
The base sequence of a gene determines the amino acid sequence in a polypeptide.

Question 6

Exons

Answer 6

sequences of bases in a gene that code for the polypeptide

Question 7

Introns:

Answer 7

(In eukaryotes), sequences of bases in a gene that do not code for polypeptides.
Differences in base sequences of alleles of a single gene may result in non-functional proteins, including non-functional enzymes.

Question 8

Compare tRNA vs mRNA

Answer 8

tRNA
Clover shaped
Standard length
Has an amino acid binding site
anticodon
tRNA has H bonds between complementary base pairs
Limited number of types (64)
mRNA
Linear
Variable length (depends on the length of gene)
Many different types (depends on the gene)
No H-bonding
No base pairs

Question 9

Compare DNA Vs RNA

Answer 9

Similarities:
Contain phosphate
Made up of nucleotides
Contains organic bases (A, C and G) (not T as it is replaced by U in RNA)
Pentose sugar
Differences
RNA single stranded
RNA has non-coding strands (introns) removed 
Ribose sugar in RNA deoxyribose in DNA
U in riobose replaces the T
3 types of RNA, only one DNA
Smaller than DNA

Question 10

Compare the structures of RNA and DNA;

Answer 10

Alike
both have phosphate/phosphoric acid/PO4;
bases/named bases/accept letters;
nucleotides;
pentose sugar;
Different
DNA deoxyribose;
DNA thymine;
DNA double stranded;
DNA larger/longer;
DNA one form RNA 3 types;

Question 11

Describe translation and transcription

Answer 11

Transcription
Section of DNA unwinds / uncoils; 
DNA separates, h-bonds break
RNA nucleotides align;
complementary base pairing / example of pairing;
U replaces T
mRNA polymerase (joins nucleotides);
mRNA is modified, introns are removed
Translation
mRNA moves into cytoplasm / through nuclear pore / to ribosome;
tRNA carries specific amino acid;
mRNA read in codons / triplets;
anticodon of tRNA matches codon of mRNA;
ATP used in activation / joining amino acids;
amino acids join by peptide bonds;
tRNA used repeatedly;
sequence of bases / codons determines sequence of amino acids;

Question 12

Describe what happens during translation.

Answer 12

Codons on mRNA;
anticodons on tRNA;
20 types tRNA molecule
specific amino acid attached to tRNA;
peptide bonds formed

Question 13

Describe the role of tRNA in the process of translation.

Answer 13

Anticodon complementary to codon/reads message on mRNA;
Specific amino acid;
Carried/transferred (to ribosome);
Correct sequence of amino acids along polypeptide;

Question 14

Comparison of replication and transcription

Answer 14

Similarities
H bonds break and the DNA unzips
DNA acts as a template for complimentary base
Polymerase enzymes are involved
Differences
U replaces T in RNA
In replication all the DNA is copied, in transcription on sections are copied
Only one strand is used as a template in transcription (antisense strand), both strands are used in replication
RNA polymerase in transcription whereas DNA polymerase is sued in replication
mRNA is produced in transcription, DNA is produced in replication