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DNA, genes and chromosomes. DNA and protein sysnthesis - pack 9 > genetic information > Flashcards

genetic information Flashcards

1
Q

why does the DNA molecule have to be stable

A

because it has to pass genetic information from one generation to the next

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2
Q

which nitrogen bases are purines

A

adenine and guanine
double string structures

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3
Q

which nitrogen bases are pyrimidines

A

thymine and cytosine
single ring structures

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4
Q

how many different types of amino acids are there in living organisms

A

20

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5
Q

what determines the number ans sequence of amino acids in each polypeptide

A

DNA sequence

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6
Q

what are 3 features of DNA in prokaryotic cells

A

short
circular
not associated with proteins

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7
Q

how is DNA in eukaryotic cells different from prokaryotic

A

very long
linear
associated with proteins

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8
Q

what 2 molecules make up a chromosome in eukaryotic cells what two types

A

DNA molecule
associated protein- histones

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9
Q

what is the monomer of DNA

A

nucleotides

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10
Q

what two molecules do genes code for

A

amino acid sequence of a polypeptide
a functional RNA

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11
Q

what is a gene locus

A

position of a gene on a map of a chromosome

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12
Q

what are stop codons

A
  • do not code for an amino acid
  • if they appear in polypeptide chain then no amino acid would be added
  • chain would stop in this place
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13
Q

what is another name for a stop codon

A

nonsense codon

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14
Q

what does the genetic code being non overlapping mean

A

each base is only read once in the code

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15
Q

the genetic code is said to be universal what does this mean

A

the same DNA triplet codes for the same amino acid in all living organisms

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16
Q

what factors cause DNA to mutate

A
  • mutations can occur spontaneously when DNA replicates
  • radiation
  • chemicals/metals
  • biological agents
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17
Q

what is a frame shift mutation

A

the insertion or deletion of nucleotide bases in numbers that are not multiples of three

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18
Q

why might a deletion mutation have a greater affect if it is near the start of the gene rather than the end of the gene

A
  • it will change the amino acids after the point of mutations
  • may create a stop codon and so terminate the polypeptide chain
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19
Q

what % of DNA codes for polypeptides or RNA?

A

very small 1-2%

20
Q

microsatellite

A
  • short tandem repeats that consists of 1 to 9 base pairs monomer repeating sequences
  • rich with A and T bases
21
Q

minisatellite

A
  • tandem repeats with a monomer repeat length of 10 to 100 base pairs
  • rich with C and G bases
22
Q

what are the non coding parts of DNA within genes known as

A

introns

23
Q

what is the genome of a cell

A

genetic material of an organism
consists of DNA
includes both genes and the non- codingsequences of DNA/RNA

24
Q

what is the proteome of a cell

A

entire set of proteins expressed by a genome, cell, tissue or organism at a certain time
under defined conditions

25
Q

which enzyme unzips the DNA

A

DNA helicase

26
Q

what enzyme is used to covalently join the RNA nucleotides to make mRNA

A

RNA polymerase

27
Q

how is mRNA adapted to its function

A
  • small - fit through pore
  • contains a series of nucleotides
  • unstable molecule - hydrolysed quickly when it is no longer needed
28
Q

what is a transcription factor

A

protein that binds to specific DNA sequences
controlling the rate of transcription

29
Q

how do transcription factors act

A
  • move from cytoplasm to DNA
  • binds to specific gene/ binds to promoter
  • allows/ blocks binding of RNA polymerase
30
Q

what is a promoter

A

a region of DNA that RNA polymerase and the necessary transcription factors bind to

31
Q

what is an intron

A

a region of DNA within a gene that does not code for amino acids within a protein

32
Q

what is an exon

A

it is a region of DNA within a gene that codes for the amino acids within a protein

33
Q

what molecule must be hydrolysed to provide the energy needed for the production of the peptide bond

A

ATP

34
Q

what two types of molecules are ribosomes made from

A

rRNA and protein

35
Q

three stages of translation

A

stage 1- initiation
stage 2- elongation
stage 3- termination

36
Q

stage 1 of translation initiation

A
  • A tRNA brings first amino acid into position- anticodon forms Hydrogen bonds with complementary codon
  • start codon is AUG so first amino acid always methionine
  • the ribosomes stabilises the binding of the tRNA to the mRNA
37
Q

stage 2 of translation elongation

A
  • tRNA amino acid complexes are held close together by the ribosome: amino acids joined by a peptide bond formed by a condensation reaction
  • once amino acid has been attached to the polypeptide chain, the tRNA that carried it there will now go back to the cytoplasm to pick up another amino acid of the same type
38
Q

stage 3 of translation termination

A

when ribosome reaches a stop codon, the ribosome mRNA and completed polypeptide chain

39
Q
A
40
Q

ribosomes are connected in groups called

A

polyribosomes or polysomes
held together by a thin strand of ribosomal RNA

41
Q

how is a tRNA molecule adapted to its function

A
  • each tRNA has an amino acid binding site, enabling it to carry a specific amino acid in the cytoplasm
  • has anticodon complementary to a codon on mRNA- determines order of amino acids in polypeptides
  • more stable than mRNA enabling them to pick up another amino acid
42
Q

what type of bonds are important in secondary structure

A

hydrogen bonds

43
Q

what are the names of the 2 types of secondary structure

A

alpha helix and beta pleated sheets

44
Q

what are the names of the 3 types of bond present in a tertiary structure

A

hydrogen, disulfide and ionic bonds

45
Q

which bond is least likely to break if a protein is denatured

A

disulfide bonds

46
Q

which amino acid is often removed from the beginning of a polypeptide chain after translation

A

methionine

DNA, genes and chromosomes. DNA and protein sysnthesis - pack 9 (1 decks)

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