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A2 OCR Biology > Cellular control (from LOs) > Flashcards

Cellular control (from LOs) Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Define mutation

A

Change in the DNA.

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2
Q

Define chromosome mutation

A

Gain/ loss of whole/part of chromosome.

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3
Q

Define DNA mutation

A

Change in base sequence.

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4
Q

Define mutagens

A

Increases chance of a mutation occuring

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5
Q

Define somatic mutation

A

Mutation in cell which is not a gamete/ cannot be passed on to offspring.

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6
Q

Define allele

A

Version of a gene.

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7
Q

List some examples of mutagens

A

UV, tar, radiation

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8
Q

State when DNA mutations may occur

A

When DNA replicates

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9
Q

Explain the differences between a somatic mutation and a mutation that occurs during meiosis

A

Somatic mutation not passed onto offspring, mutation occurs during meiosis = gamete has new allele = mutation passed onto offspring.

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10
Q

What are the 3 types of mutation?

A

Point, insertion and deletion.

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11
Q

What happens in a point mutation?

A

1 base replaces another

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12
Q

What happens in an insertion mutation?

A

1 extra nucleotide added

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13
Q

What happens in a deletion mutation?

A

1 nucleotide removed.

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14
Q

Explain what is meant by the term “frame shift”

A

All codons after the mutation are changed

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15
Q

State and explain which type of DNA mutation is likely to have the greatest effect on the protein produced.

A

Insertion/deletion
cause a frame shift
all codons after the mutation changed
so secondary and tertiary structures changed, so shape changed = not function or function differently.

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16
Q

Explain why a substitution mutation may not affect the protein produced

A

Code is degenerate so new codon may still code for the same amino acid.

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17
Q

Define gene expression

A

Whether a gene is switched on or off (i.e. whether a gene is used to produce a protein or not).

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18
Q

Define operon

A

Length of DNA which is made of structural genes and control sites.

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19
Q

Define enzyme induction

A

Switching on the gene to make the enzyme when needed.

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20
Q

Define inducer

A

Molecule which causes the production of the protein/ switches the gene on.

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21
Q

Define repressor protein

A

Molecule which switches the gene off.

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22
Q

Define transcription level

A

This means controling if transcription happens or not.

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23
Q

Define transcription factor

A

Molecule (usually a protein or group of proteins) which binds to the operator region before a gene, making it possible for the RNA polymerase to bind so transcription can occur.

24
Q

Explain why there are large numbers of some proteins but only small numbers of other proteins in a cell

A

Genes switched on/ off at different levels.

25
Q

Name the 2 enzymes required to metabolise lactose

A

Lactose permease and beta- galactosidase

26
Q

What is the function of lactose permease?

A

Transports lactose into the cell.

27
Q

What is the function of beta-galactosidase?

A

Hydrolyses lactose/ converts to glucose and galactose.

28
Q

Explain why, when supplied with lactose, bacteria cannot initially respire it

A

Don’t have these 2 enzymes

29
Q

State the function of each part of the lac operon

A 
P and O are control sites,
RNA polymerase needs to bind to P
The repressor binds to O, preventing RNA polymerase binding.
Z codes for B galactosidase
Y codes for lactose permease
30
Q

Name the gene which is not part of the operon but whose product helps with the functioning of the operon.

A

Regulatory gene

31
Q

Describe how the lac operon works when there is no lactose

A

B galactosidase and lactose permease genes are switched off.
Regulator genes expressed
Repressor protein synthesised
Repressor protein binds to operator region
Repressor protein covers part of promotor region
RNA polymerase cannot bind to promoter
No transcription
No B galactosidase and lactose permease

32
Q

Describe how the lac operon works when lactose is present

A

B galactosidase and lactose permease genes are switched on.
Lactose is the inducer
Binds to complementary site on repressor protein
Repressor protein changes shape
Repressor protein cannot bind to operator region
RNA polymerase can bind to promoter region
B galactosidase and lactose permease genes are transcribed
B galactosidase and lactose permease genes are produced.

33
Q

Define post transcription

A

Events that occur after transcription (after mRNA has been made)

34
Q

Define post translation

A

Events that occur after translation (after the protein has been made)

35
Q

Define intron

A

Non-coding DNA (sequence of bases which do not code for amino acids in the protein).

36
Q

Define primary mRNA

A

mRNA which is produced during transcription.

37
Q

Define mature mRNA

A

mRNA that is used at the ribosome to make the protein.

38
Q

Outline how primary mRNA is converted to mature mRNA

A

Introns are removed, by the enzymes

39
Q

Describe how proteins are activated post translation

A

By cyclic AMP, this changes their tertiary structure, to make shape of protein complementary to shape of molecule it needs to bind to.

40
Q

Define mitosis

A

Cell division which produces clones

41
Q

Define differentiation

A

Process cells go through to become specialised

42
Q

Define homeobox gene

A

Gene which controls development of organism

43
Q

Define polarity

A

Difference in charge.

44
Q

Define hox cluster

A

Several homeobox genes located together

45
Q

What is the anterior side of an organism?

A

Head

46
Q

What is the posterior side of an organism?

A

Tail

47
Q

What is the dorsal side of an organism?

A

Top

48
Q

What is the ventral side of an organism?

A

Bottom

49
Q

What are 3 types of homeobox genes?

A

Maternal effect gene, homeobox gene and segmentation gene.

50
Q

What is the function of the maternal effect gene?

A

Determine polarity of the embryo

51
Q

What is the function of the homeobox gene?

A

Determine identity of each segment

52
Q

What is the function of the segmentation gene?

A

Determine polarity of each segment

53
Q

Describe the 2 types of homeotic selector genes

A

Thorax and abdomen selector genes.

54
Q

Describe the effect a mutation in a homeobox selector gene could have.

A

Body part in the wrong position.

55
Q

State what type of protein homeobox genes code for

A

Transcription factors

56
Q

Explain how homeobox genes control development

A

Each homeobox gene codes for one transcription factor, this then switches on/off genes to make that segment.

57
Q

Describe the relationship between order of activation and location and expression of homeobox genes

A

Activated in the order they are expressed along the organism.

A2 OCR Biology (6 decks)

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