Storing and Using Genetic Information

Question 1

Phenotype

Answer 1

outward, physical manifestation of organism

Question 2

Genotype

Answer 2

full hereditary information of an organism

Question 3

What is a nucleotide composed of?

Answer 3

• sugar
• base
• phosphate group

Question 4

What sugar is found in DNA?

Answer 4

2’-deoxyribose

Question 5

Describe the curve of the double helix.

Answer 5

• Contains major and minor curves which provide stability

- Right-handed- spirals clockwise

Question 6

What are the complementary base pairs?

Answer 6

• adenine and thymine (uracil in RNA)

- cytosine and guanine

Question 7

Describe the structure of the nucleus

Answer 7

• largest organelle (usually)
• contains cells genetic material
• site of DNA replication and decoding

Question 8

What are chromosomes?

Answer 8

a single piece of DNA containing many genes, regulatory element and other nucleotide sequences

Question 9

What is chromatin?

Answer 9

the mixture of DNA, proteins and RNA that package DNA within the nucleus

Question 10

What is the difference between heterochromatin and euchromatin?

Answer 10

• Heterochromatin= condensed and silenced

- euchromatin= extended and expressed

Question 11

What do transcription and replication both require?

Answer 11

Two strands of DNA to separate temporarily to allow enzymes access to the DNA template

Question 12

What possess barriers to enzymes?

Answer 12

nucleosomes and folding of chromatin

Question 13

What are the 2 major mechanisms by which chromatin is made more accessible?

Answer 13

• histones can be enzymatically modified
• histones can be displaced by chromatin remodelling complexes
• both processes are reversible

Question 14

Semi-conservative

Answer 14

one half of each new molecule of DNA is old, one half new

Question 15

In what direction does DNA replication take place?

Answer 15

5’ to 3’

Question 16

Where are Okazaki fragments formed

Answer 16

on the lagging strand

Question 17

What does telomerase do?

Answer 17

replicates the 5’ end of the lagging strand

Question 18

Exon

Answer 18

Coding region of DNA

Question 19

Intron

Answer 19

non-coding region of DNA

Question 20

Degeneracy

Answer 20

All of the amino acids (exc methionine and tryptophan) are encoded by more thatn 1 codon.

Question 21

What is the mutation behind SCA?

Answer 21

single point mutation where hydrophilic glutamate is substituted to hydrophobic valine

Question 22

What is mRNA?

Answer 22

• transcribed from DNA

- carries information for protein synthesis

Question 23

What is the major role of RNA?

Answer 23

to participate in protein synthesis

Question 24

Alternative Splicing

Answer 24

a process by which exons of the RNA produced by transcription are reconnected in multiple ways during RNA splicing

Question 25

What determine the reading frame of RNA sequence

Answer 25

initiation codon

Question 26

What is the major role of tRNA?

Answer 26

to translate mRNA into amino acid sequence and acts as an adapter molecule between the coded amino acid and the mRNA

Question 27

Describe rRNA?

Answer 27

• component of ribosomes
• rRNA molecules are produced in the nucleus
• transported to cytoplasm, where they combine with proteins to form a ribosome

Question 28

What is a polysome

Answer 28

when several ribosomes translate mRNA at one time