M6 C19: cellular control

Question 1

What is the structure of DNA?

Answer 1

phosphate
pentose sugar
nitrogenous base

Question 2

what is a mutation?

Answer 2

change in the sequence of bases

Question 3

what is different between purine and pyrimidines

Answer 3

purines- have a double ring
pyrimidines- single ring

Question 4

what are purines?

Answer 4

adenine
guanine

Question 5

what are pyrimidines?

Answer 5

cytosine
thymine

Question 6

why is dna degenerate?

Answer 6

more codons than amino acids so there is multiple combinations for same amino acids

Question 7

why is dna non overlapping?

Answer 7

3 basesare done at a time so no codons overlap

Question 8

why is the dna code universal?

Answer 8

everyone has the same ammino acids and codon combinations

Question 9

what is insertion?

Answer 9

extra nucleotide may be added which messes up the codons after it changes the protein

Question 10

what is deletion?

Answer 10

nucleotide is removed. this moves all the nucleotides up 1 space so the wanted AA aren’t coded for

Question 11

what is frame shift?

Answer 11

shifts codons back or forwards witch causes further AA to be changed including start and stop codons

Question 12

what is substitution?

Answer 12

a nucleotide is substituted for another. it can change the AA made or the tertiary strucuture. could also change the shape/ function

Question 13

what is a nonsense change?

Answer 13

when a change leads to a stop codon/AA being coded for shortening the protein. this can lead to loss of function

Question 14

what is a missense change?

Answer 14

changes amino acid may lead to a big or a minimal change. this could lead to a loss of function/ shape or improved function

Question 15

what is a silent change?

Answer 15

when change has no affect on the amino acid that is produced

Question 16

what are the effects of mutations?

Answer 16

neutral
harmful
beneficial

Question 17

what is a neutral effect?

Answer 17

caused by a silent mutation where normal proteins are still synthesised. phenotype isnt changed

Question 18

what is a harmful effect?

Answer 18

proteins synthesised are non functional and the phenotype is negatively impacted

Question 19

what is a beneficial effect?

Answer 19

the change may make it work better or carry out something new more useful

Question 20

what are some causes of mutations?

Answer 20

radiation eg- x rays, gamma
smoking, drugs and alchohol
chemicals in caffine
UV light

Question 21

what are some diseases caused by mutations?

Answer 21

cystic fibrosis
huntingtons disease
protooncogenes change to oncogenes which can cause uncontrolled cell division which causes cancer

Question 22

how can mutations lead to difference in shape?

Answer 22

new bases= new amino acids which could have different bonds, changes the shape as bonds may be different

Question 23

what are transcription factors?

Answer 23

proteins which move in from cytoplasm to DNA. they attach rna polymerase to dna. proteins that bind to specific regions of DNA to control the transcription of genes

Question 24

what do trancription factors do?

Answer 24

bind to the promoter region of a gene (i.e. the region of DNA ‘upstream’ of the gene that controls the expression of the gene)
binding can either allow or prevent the transcription of the gene from taking place

Question 25

what is a promoter?

Answer 25

controls where the gene is trancribed

Question 26

what does a transcription inhibitor do?

Answer 26

wont attatch to the promoter

Question 27

what is special about oestrogen?

Answer 27

steroid therefore lipid soluble so can pass through the bilayer/membrane

Question 28

what does oestrogen do?

Answer 28

binds to an oestrogen receptor
which causes a change in the shape of the receptor
As a result, the receptor moves away from the protein complex it is normally attached to and binds to the promoter region of one of its target genes
This allows RNA polymerase to bind and to begin transcribing that gene