8A- Mutations and expressions

Question 1

How to cells control metabolic reactions

Answer 1

-regulating the transcription and translation of their genome

Question 2

Genome

Answer 2

the complete set of genes in a cell

Question 3

Proteome

Answer 3

all the proteins made by a cell

Question 4

Translocation mutation

Answer 4

-sequence of bases is moved from one location in the genome to another. within the same chromosome or to different

Question 5

Types of base sequence mutations

Answer 5

1-substitution 
2-deletion
3-addition
4-duplication
5-Inversion
6-translocation

Question 6

mutagenic mutation

Answer 6

increases the rate of DNA mutations

Question 7

gene

Answer 7

a section of DNA that codes for a protein (polypeptide) which results in a characteristic

Question 8

Genetic disorder

Answer 8

inherited disorders caused by abnormal genes or chromosomes

Question 9

Hereditary mutations

Answer 9

-gamates containing a mutation that are fertilised and passed onto the offspring

Question 10

Gene mutations occur

Answer 10

randomly and spontaneously

Question 11

degenerate nature of genetic code

Answer 11

same amino acids are coded for by more than one DNA triplets

Question 12

Universal nature of genetic code

Answer 12

same DNA base triplets code for the same amino acids in all organisms

Question 13

Frame-shift mutations

Answer 13

addition, deletion and duplication of DNA base sequences in a gene can cause the base triplets/codons to be read in a different way downstream of the mutation changing the amino acid base sequence in the polypeptide chain altering protein structure postion of bonds

Question 14

silent mutation

Answer 14

substitution mutations that don’t change the amino acid sequence due to degenerate nature of the genetic code

Question 15

benefits of hereditary mutations

Answer 15

drives evolution

Question 16

Ways to increase rate of mutations

Answer 16

1-Altering Bases- Base analogs can substitute for a base during DNA replication changing the base sequence of DNA
2-Altering Bases- chemical delete or alter bases
3-Changing the structure of DNA- causes problems during DNA replication.

Question 17

degenerate nature of genetic code means

Answer 17

not all mutations change the sequence of amino acids coded for

Question 18

Transcription Factors

Answer 18

a protein molecule that controls the rate of a transcription of a gene by binding to the promoter region at the start their target gene.

Question 19

Transcription factors move from

Answer 19

the cytoplasm to the nucleus

Question 20

target genes

Answer 20

genes they control the expression of

Question 21

Promoter regions

Answer 21

specific DNA sequences at the start of a target gene that tells RNA Polymerase to start producing mRNA

Question 22

activators

Answer 22

stimulate and increase the rate of transcription- help RNA Polymerase to bind to the start of the target gene DNA

Question 23

Repressors

Answer 23

inhibit and decrease the rate of transcription- bind to the start of the target gene preventing RNA Polymerase from binding to the start of the target gene DNA

Question 24

Oestrogen in transcription

Answer 24

steroid hormone that can affect the transcription by binding to a transcription factor called an oestrogen receptor forming O-Oestrogen receptor complex

Question 25

Oestrogen receptor

Answer 25

Transcription factor that oestrogen binds to which affects transcription rate

Question 26

Role of Oestrogen In Transcription

Answer 26

1-Oestrogen (steroid hormone) binds to Oestrogen receptor (transcription factor) forming Oestrogen-Oestrogen receptor complex
2-complex moves from the cytoplasm to the nucleus where it binds promoter region at star of target gene
3-O-OR complex acts as an activator or repressor of Transcription
4- helps or inhibits RNA Polymerase bind to the start of a target gene promoters (specific DNA sites )

Question 27

Why aren’t all cells affected by oestrogen

Answer 27

They don’t have oestrogen binding sites on the cell surface membrane

Question 28

RNAi (interference)

Answer 28

small, double stranded non-coding RNA molecules stop mRNA from target genes being translated into proteins in eukaryotes

Question 29

siRNA and (miRNA in plants)

Answer 29

1-mRNA transcribed + leaves nucleus for cytoplasm via nuclear pore
2-IN CYTOPLASM double stranded siRNA associates with proteins and unwinds
3-one strand selected other degraded
4-selected single strand binds to target mRNA
5-base sequence of siRNA is complementary to base sequence sections on target mRNA
6-proteins associated with siRNA cut mRNA into fragments so can’t be translated
7- cut up mRNA fragments degraded in processing body

Question 30

miRNA in mammals

Answer 30

1-miRNA isn’t fully complementary to target mRNA so less specific and can target multiple mRNA molecules
2-when first transcribed miRNA exists as long folded strand thats processed into a double stands and then into one mRNA molecule
2- 1 strand associates with proteins and binds to target mRNA in the cytoplasm and other degraded.
3-miRNA-protein complex blocks translation of target mRNA
4-mRNA stored or degraded in processing body