Gene Expression

Question 1

Universal

Answer 1

Same triplets code for the same amino acids in all organisms

Question 2

Non overlapping

Answer 2

Ribosomes read each base once in codons

Question 3

Degenerate

Answer 3

More than one codon codes for an amino acid

Question 4

Mutation

Answer 4

Random spontaneous change to DNA base sequence resulting to change in primary structure of polypeptide

Question 5

Substitution mutation

Answer 5

Altering a base in triplet.Silent mutation s DNA base sequence is generate

Question 6

Addition/ deletion mutation

Answer 6

Removal or addition of a base leading to frame shift

Question 7

Chromosomal mutation

Answer 7

Chromosome non disjunction where one daughter cell has no chromosomes

Question 8

Mutagenic agents

Answer 8

1.High energy ionisation leads to damage / alter n DNA base sequence
2. DNA reactive chemicals such as nitros oxide which confers bases
3. Biological agents such as bacteria and viruses

Question 9

Stem cells

Answer 9

Divide by mitosis into 2 genetically identical cells. One remains as a stem cell and other differentiates into a specialised cell by translating part of their DNA

Question 10

Order of stem cell

Answer 10

TPMU
Totipotent
Pluripotent
Multipotent
Unipotent

Question 11

Totipotent stem cells

Answer 11

Divide and differentiate into any type of cell and produce a whole new organism. Found up to first 8 mammalian stages for a limited time

Question 12

Pluripotent

Answer 12

Divide an unlimited number of times and differentiate into any type of cell . Found in an embryo

Question 13

Multipotent

Answer 13

Divide a limited number at time and differentiate into a limited number of cells found in mature mammal tissue

Question 14

Uni potent

Answer 14

Divide a limited number of time and differentiate into one type of cell

Question 15

Application of stem cells to medical research

Answer 15

Research into producing organs for transplant
Research into cancer
Use of stem cells to cure diseases such as Parkinson’s disease
Producing tissue for skin graft

Question 16

Promoter region

Answer 16

Base sequence found before a gene that controls the expression of that gene

Question 17

Suggest how a transcription factor increases gene expression

Answer 17

Transcription factor by binding to promoter region in DNA as specifically complementary and stimulates RNA to increase transcription

Question 18

Describe how oestrogen act as a transcription factor?

Answer 18

1. Oestrogen is lipid soluble and diffuses through phospholipid bilayer through the nuclear envelope
2. Complementary to oestrogen receptor so binds and changes tetirtary structure of proteins receptor
3. This releases the transcription factor
4. Transcription factor is complementary to specific sequence of DNA known as printer biometric and binds
5. This stimulates RNA polymerase to transcribe the gene increasing transcription so more MRNA produced

Question 19

How does siRNA and miRNA work ?

Answer 19

SiMRNA/miRNA specifically complementary to name gene/protein mRNA
So binds by hydrogen bonding
Resource in destruction of mRNA or ribosome from binding to mRNA so stops translation from inhibiting
So reduces translation of named protein
So reduces named protein in cell so last name protein function

Question 20

Why could some protein still be made even if interfering RNA??

Answer 20

1. More mRNA has been transcribed and there is interfering or mRNA so not all mRNA bound to si mRNA/ Ri amor
2. Not all mRNA is destroyed.

Question 21

Define Epigenetics

Answer 21

Heritable changes in the gene function without changes to the DNA sequence

Question 22

Tumour suppressed gene

Answer 22

Codes for a protein that stops cell division

Question 23

Proto-oncogene

Answer 23

Codes for protein that starts cell division

Question 24

Cancer

Answer 24

Uncontrolled cell division

Question 25

Tumour

Answer 25

Mass of abnormal cells from uncontrolled mitosis

Question 26

Difference between malignant and benign tumours ?

Answer 26

Malignant =. Can be metastasis and spread around the body. Benign = cannot be metastasis and will not spread to other parts of the body

Question 27

What is methylation?

Answer 27

Addition of methyl groups to DNA which Titans are even more so no RNA polymerase can bind therefore no transcription

Question 28

What is acetylation?

Answer 28

Addition of acetal groups to his stone proteins which loosened the DNA double helix coil therefore RNA polymerase can bind and transcription of DNA

Question 29

Does the tumour suppressed gene have to be expressed?

Answer 29

No , in order for the cell cycle to start. This means that the proto onco gene needs to be expressed

Question 30

Describe how tumours could form because of Epigenetics to the proto-oncogenes?

Answer 30

Needs to be expressed Less methylation of proto-oncogene’s DNA More acetylation of his stone proteins More transcription of gene More mRNA formed More translation of mRNA More named protein that starts cycle Lead to uncontrolled cell division Formation of mass of abnormal cells

Question 31

Describe the result in mutation to the Exons in the genes

Answer 31

Change in amino acid sequence Change in structure due to different placements of hydrogen ionic and disulphide bonds between all groups of different amino acids Faulty protein lead to uncontrolled cell division /can’t start the cycle

Question 32

Mutation in promoter region of genes

Answer 32

Mutation in promoter region Transcription factor cannot bind as not specifically complementary to DNA So RNA polymerase is not stimulated so no transcription of gene no mRNA formed

Question 33

Keyword

Answer 33

Expression Cancer is uncontrolled cell division