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Protein Synthesis And DNA Flashcards

1
Q

What is a gene?

A

A small section of DNA

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2
Q

How do genes control an organisms phenotype

A

Genes code for specific Amino acids to produce a specific protein/polypeptide

E.g enzymes that control biochemical reactions

Therfore control an organisms development and activities

Along with environmental factors genes determine phenotype

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3
Q

What determines an organisms phenotype?

A

Along with environmental factors genes determine phenotype

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4
Q

What is a locus

A

The position on the chromosome where a gene is found

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5
Q

What is a sequence of 3 bases on DNA called

A

Triplet

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6
Q

Describe the difference between intros and exons

A

Exons= expressed

Introns=not expressed

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7
Q

How many bases code for an Amino acid?

A

3

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8
Q

How did scientists conclude how many bases coded for an Amino acid?

A

If 1 base coded for 1 Amino acid there would be 4 Amino acids

If 2 bases coded for 1 Amino acid there would be 8 Amino acids

If 3 bases coded for 1 Amino acid there would be 64 Amino acids which are plenty to code for all 20 naturally occuring Amino acids

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9
Q

How many Amino acids are there

A

20

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10
Q

Do chloroplasts have more or less genes than mitochondria, why?

A

More because Photosynthesis requires more enzymes than Respiration

Enzymes are proteins that are coded for by genes

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11
Q

Name the main features of the genetic code

A

Degenerate

Non overlapping

Universal

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12
Q

What does degenerate code mean

A

One Amino acid can be coded for by various triplet codes

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13
Q

What does non overlapping mean

A

Every base is only read once

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14
Q

What is meant by a universal code?

A

Same triplets usually code for the same Amino acids in all organisms

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15
Q

How does the genetic code provide indirect evidence for evolution?

A

Universal code means there is a shared biochemistry so indirect evidence for shared ancestor

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16
Q

What does non functional DNA always start and end in?

A

Start with triplet coding for methanionine

End with stop codon

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17
Q

Compare where the genetic code if found in prokaryotes and eukaryotes

A

Pro= cytoplasm

Eu= nucleus

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18
Q

Compare the name of the molecule where the genetic code is found in prokaryotes and eukaryotes

A

Pro= nucleiod or plamsid

Eu= chromosome

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19
Q

Compare the shape of the genetic code found in prokaryotes and eukaryotes

A

Pro= circular

Eu= linear

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20
Q

Compare the association of proteins in the genetic code found in prokaryotes and eukaryotes

A

Pro=none

Eu= with histones

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21
Q

Compare the length of the genetic code found in prokaryotes and eukaryotes

A

Pro= short

Eu= longer

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22
Q

Compare the prevalence of Introns in the genetic code found in prokaryotes and eukaryotes

A

Pro= none

Eu= yes

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23
Q

Do prokaryotes have Introns?

A

No, only exons

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24
Q

Do the genes of chloroplast and mitochondria have Introns?

A

No, same a prokaryote

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25
When are chromosomes visible
During semi-conservative DNA replication
26
What is the difference between sister chromosomes and homologous chromosomes?
Sister chromatids are genetically identical and joined by centro mere Homologous pairs are not genetically identical and aren't joined by a centromere
27
What phase of the cell cycle are chromosomes visible
Synthesis
28
What are sister chromatids?
Genetically identical arms of a chromosome
29
Describe how DNA is arranged
Double helix, wound around histones (DNA histone complex) Which are coiled and looped Compact into a chromosome
30
Why are the numbers of chromosomes in organisms usually even
So that they can pair up for DNA replication
31
Define homologous chromosomes
Pair of chromosomes with the same genes at same locus but not genetically identical One maternal one paternal
32
What is the diploid number
23 homologous pairs
33
What does n stand for in 2n
Haploid number
34
How is the diploid number represented algebraically
2n
35
What is the haploid number
23 chromosomes (not paired)
36
Why are gametes haploid
So that upon fertilización the diploid number is restored
37
What is an allele
A form of gene
38
How do mutations cause a different polypeptide to be synthesised?
Mutations cause a different base sequence creating different allele meaning different protein is coded for.
39
Define genome
Complete set of genes in a cell (including mitochondria)
40
Define proteome
Complete set of proteins able to be produced by a genome
41
Give difference between definition of proteome in proteome and complete proteome
Complete Proteome= proteins produced by specific cell under specific conditions Proteome = complete set of proteins produced by a genome
42
Describe the structure of mRNA
Single stranded helix Short Polynucleotide polymer
43
What are codons
Three bases on a strand of MRNA
44
Why does MRNA need to be produced
Because DNA is too large to exit the nucleus | MRNA is able to diffuse out of the nucleus via a nucleur pore
45
Describe and explain the chemical stability of MRNA
Not very stable, no hydrogen bonds Easily broken down Prevents any unwanted protein Synthesis to reduce waste
46
Describe the structure of tRNA
Clover-leaf shape Anticodon loop One end of Polynucleotide chain extends beyond the other allowing for Amino acid attachment Folds back on itself so has H bonds
47
How many TRNA molecules are there and why
64 to account for all 64 combinations of bases
48
What are the different types of RNA
TRNA-bring Amino acids to ribosome MRNA- transfer genes for protein Synthesis RRNA - make up ribosome
49
Order DNA MRNA and TRNA in increasing size
TRNA MRNA DNA
50
Define functional RNA
RNA not involved in protein Synthesis
51
What sugar is TRNA made of
Ribose
52
What is the func of MRNA
Act as scaffold and template for protein Synthesis
53
What is the func of TRNA
Carry Amino acids to ribosome
54
What determines the amount of TRNA and RRNA present in a cell
Metabolic activity
55
What enzymes are involved in transcription
DNA helicase RNA polymerase
56
Describe how transcription occurs
DNA helicase breaks the hydrogen bonds between bases causing DNA to unwind and reveal template strand Hydrogen bonds form between complementary bases on DNA and free RNA nucleotides (complementary base pairing). RNA polymerase attaches to start of template and catalyses condensation reaction between RNA nucleotides to form phosphodiester bonds. Pre-mRNA forms RNA polymerase reaches stop codon and detaches Splicing
57
Why are only 12 bases exposed at a time during transcription
DNA rejoins once RNA polymerase passes
58
Name the stages of protein Synthesis
Transcription | Translation
59
Describe how Splicing occurs
Introns are removed from PRE-MRNA forming mRNA
60
Why is only one Polynucleotide strand a template in transcription
RNA polymerase has specifically shaped active site so only moves in one direction down strand
61
Why is Splicing important
Without it a non-functional protein or no protein would be produced
62
State what is meant be translation
Synthesis of polypeptide chain
63
Describe translation
MRNA associates with ribosome so 2 codons are in ribosome TRNA's with complementary Anticodons form H bonds with codon on mRNA Peptide bond forms between Amino acids on tRNA using enzymes and ATP in condensation reaction Ribosome moves forward on codon repeating process as tRNA molecules are released At stop codon release factor causes ribosome, tRNA and mRNA to detach. Released polypeptide Folds and accosiates with prosthetic groups
64
What is a polysome
Multiple ribosomes working on a mRNA strand at once
65
Why do polysomes form?
Faster production of polypeptide
66
How can you tell where the start of an mRNA molecule is?
The longest polypeptide chain coming off a ribosome= near end

biology (28 decks)

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