Storing and using genetic information

Question 1

What is DNA?

Answer 1

chain of nucleotide monomers

Question 2

What does a nucleotide consist of?

Answer 2

sugar
base
phosphate group

Question 3

How many hydrogen bonds for Gs and Cs?

Answer 3

3

Question 4

How many hydrogen bonds for As and Ts?

Answer 4

2

Question 5

What is chromatin at the simplest level?

Answer 5

double stranded helical structure of DNA

Question 6

What is a nucleosome?

Answer 6

each nucleosome consists of eight histone proteins around which the DNA wraps around1.65 times

Question 7

What is a chromatosome?

Answer 7

consists of a nucleosome plus the H1 histone

Question 8

What is chromatin?

Answer 8

chromatin is the name given to the mixture of DNA, proteins and RNA that package DNA within the nucleus

Question 9

What are the two forms of chromatin?

Answer 9

heterochromatin- packaged and darker regions of chromosome
euchromatic- extended, region where the genes tend to be more active and turned on

Question 10

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

Answer 10

histones can be enzymatically modified
histones can be displaced by chromatin remodeling complexes.
These processes are reversible

Question 11

Describe what is meant by DNA replication being semi conservative?

Answer 11

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

Question 12

Describe the process of DNA replication?

Answer 12

special proteins unzip the double helix by breaking the hydrogen bonds

new nucleotide molecules are then paired with the two DNA strands

replicated in 5’ to 3’ direction

Question 13

What percentage of bases is the same in all humans?

Answer 13

99.9%

Question 14

What is a set of 3 bases called?

Answer 14

codon

Question 15

Describe redundancy of genetic code?

Answer 15

you can get changes or mutations in protein sequence and it doesn’t impact it.

Question 16

What is the change in AA in sickle cell anaemia?

Answer 16

Glu substituted by Val (hydrophobic).
(GAA or GAG becomes GUA or GUG)

Question 17

How does substitution lead to sickle cell anaemia?

Answer 17

causes haemoglobin which would normally be free floating around in the the cytoplasm to form very long chains of haemoglobin.
Makes the cell the completely wrong shape for efficient oxygen transport.
And cannot flow through the blood vessels as easily and will often form blood clots and blockages in vessels

Question 18

What is transcription?

Answer 18

so encoding the sequence in DNA into RNA

Question 19

What is translation?

Answer 19

takes the RNA sequence and converts it into a polypeptide

Question 20

What does alternative splicing mean?

Answer 20

from one gene , can have multiple variants of mRNA

Question 21

Describe the process from nucleus to protein?

Answer 21

nucleus : containing all genetic info

genetic info being transcribed into mRNA

mRNA is then alternatively spliced to give individual proteins that have different functions

Processed RNA leaves nucleus and using tRNA and rRNA to produce protein

At ribosome , protein has multiple modifications

Question 22

What is role of tRNA?

Answer 22

Major role is to translate mRNA sequence into amino acid sequence.
Acts as an adapter molecule between the coded amino acid and the mRNA

Question 23

What is rRNA?

Answer 23

Component of ribosomes.
rRNA molecules are produced in the nucleus
Transported to cytoplasm, where they combine with proteins to form a ribosome.