DNA GENES AND PROTEIN SYNTHESIS

Question 1

Polypeptide

Answer 1

A chain of amino acids coded by nucleotides that make up the primary structure of a protein.

Question 2

Nucleotides

Answer 2

Monomers that make up DNA. Contain: pentode sugar, phosphate group and an organic base.

Question 3

Chromosome

Answer 3

Collection of DNA that codes for a specific part of you, organised in 23 pairs.

Question 4

Gene

Answer 4

Section of DNA on a chromosome codes for Amino Acids

Question 5

Allele

Answer 5

Alternative form of the same gene

Question 6

Locus

Answer 6

Genes fixed position on a chromosome.

Question 7

Triplet code

Answer 7

3 bases = 1amino acid

There are around 20 amino acids and 4 bases so the actual number of codes are around 64.

Question 8

Degenerate code

Answer 8

Most amino acids are coded for by more than 1 triplet, this protects against point mutations. Only a few have 1 code (Methionine ATG)

Question 9

Non overlapping

Answer 9

Each base is only in 1 triplet so it is only read once. This protects against mutation as it would only affect one triplet not 3.

Question 10

Features of the dna code.

Answer 10

• triplet code
• degenerate code
• non overlapping

Question 11

Ribosomes in eukaryotes

Answer 11

BIG 80s

Question 12

Ribosomes in Prokaryotes

Answer 12

Small 70s

Question 13

DNA in prokaryotes

Answer 13

Shorter and forms a circle, not associated with proteins (histones) so no chromosomes.

Question 14

DNA in eukaryotes

Answer 14

Longer and linear, associated with proteins (histones) so make chromosomes.

Question 15

DNA in sub cellular organelles?

Answer 15

Mitochondria and chloroplasts have dna like prokaryotes

Question 16

Super coiling 1/4

Answer 16

Bundles of tightly coiled dna are found in the nucleus of almost every cell. These are chromosomes.

Question 17

Super coiling 2/4

Answer 17

Only visible as distinct structures during mitosis/meiosis.

Question 18

Super coiling 3/4

Answer 18

When they are first visible at the start of division they appear as two threads called CHROMATIDS joined by the CENTROMERE.

Question 19

Super coiling 4/4

Answer 19

Each thread is called a chromatid as the dna molecule has already replicated to give 2 identical molecules.

Question 20

Chromosome structure

Answer 20

Each chromosome has 2 short (p) arms and 2 longer (q) arms. The ends of each arm are protected by telomeres.

Question 21

What is a NUCLEOSOME?

Answer 21

DNA wrapped many times around a histone protein

Question 22

What is a homologous pair?

Answer 22

different alleles of the same gene

Question 23

What is diploid and what is Haploid?

Answer 23

Diploid = 2 copies of each chromosome
Haploid= 1 copy of each