Storing and Using Genetic Information Flashcards

1
Q

phenotype

A

outward, physical manifestation of organism

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2
Q

genotype

A

full hereditary information of organism (even if not expressed) - genetic info that encodes phenotype

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3
Q

why are proteins all fucntionally different

A

due to their structure

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4
Q

what does protein structure depend on

A

specific sequence of amino acids

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5
Q

what is the molcecular structure of DNA (what does it contain)

A

Chain of nucleotide monomers with each nucleotide containing:
* Sugar (deoxyribose/ribose)
* Base
* Phosphate Group

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6
Q

structure of DNA

A

double helix with nucleotide base pairs connecting the two phosphate backbones. Leading and lagging strands 5’ to 3’ and vica versa. Contain minor and major groves

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7
Q

complementary base pairing

A

A-T
G-C

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8
Q

what does complementary base-pairing allow

A

to “unzip” DNA (read/expess) then put back together without breaking

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9
Q

what does the nucleus contain and what happens here

A
  • most of the cell’s genetic material (DNA)
  • replication of DNA and the first steps in decoding it for protein production
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10
Q

nucleolus

A

the largest nuclear organelle and is the primary site of ribosome subunit biogenesis in eukaryotic cells

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11
Q

what are chromosomes (what do they contain)

A

single piece of DNA containing many genes, regulatory elements and other nucleotide sequences

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12
Q

why do we fold dna into a highly ordered structure

A

takes up less space - allows for regulation

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13
Q

chromatin

what is it, sub-divided into

A

name given to the mixture of DNA, proteins and RNA that package DNA within the nucleus

Divided between heteochromatin (condensed) and euchromatic (extended) forms

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14
Q

what poses a barrier to enzymes trying to unzip dna

A

nucleosomes and folding of chromatin

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15
Q

2 main mechanisms by which chromatin is made more accessible

A
  • histones can be enzymatically modified
  • histones can be displaced bu chromatin remodeling complexes

processes are reversiable

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16
Q

dna replication: semi-conservative

A

one-half of eachh ne molecule of DNA is old; one-half new

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17
Q

how do proteins unzip the double helix

A

by breaking the hydrogen bonds

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18
Q

direction of DNA replication

A

bi-directional: only in 5’ to 3’ direction

19
Q

what happens to dna before replication during cell division

A

chromosomes/dna lines up for cell division - can split in half cleanly

20
Q

what happens to chromatin fibres to further fold dna

A

chromatin fibres repeatedly folded into a hierarch of multiple loops and coils

21
Q

when are chromosomes most compacted (and visible)

A

during metaphase

22
Q

exons

A

coding regions

23
Q

introns

A

non-coding regions

24
Q

set of 3 bases

25
what does each codon specify
a particular amino acid - recognised by tRNA
26
how many different codons code for an amino acid
usually more than one (with exeption of couple AA)
27
what can single point mutations cause and give example
**dysfunctional proteins**: mutated haemoglobin gene causes Sickle Cell Anaemia - hydrophilic Glu is substituted by the hydrophobic Val (GAA/GAG --> GUA or GUG). hydrophobic Val causes **clumping**
28
what is the primary role of RNA
participate in protein synthesis
29
3 types of RNA
* Messenger RNA (mRNA) * Transfer RNA (tRNA) * Ribosomal RNA (rRNA)
30
2 major steps of DNA replication
transcription then translation
31
role of mRNA
* transcribed from DNA * carrier info for protien synthesis
32
alternative splicing
1 gene codes for multiple RNA transcripts which give multiple proteins - allows is to have **less genes**
33
Reading frames
initiation codon of 3 nucleotides also deterimines the **reading frame** of the RNA sequence - if messed up **inhibition codon** (e.g. deletion mutation) then everything moves along 1 space (e.g. the fat cat --> hef atc at...) so completely different/non functional protein made
34
summarise process of DNA to functional protien and where this occurs
Nucleus: DNA--transcribed-->mRNA--alternative splicing--> Processed RNA leaves nucleus (to **cytoplasm**): together with tRNA and rRNA makes **protein**--> post translational modifications
35
tRNA
* role to **translate** mRNA sequence into AA sequence * acts as an adapter molecule between the coded AA and the mRNA **links codon and specific AA**
36
rRNA
* component of ribosomes * rRNA molecules produced in nucleus * transported to cytoplasm where they combine with proteins to form a ribosome
37
what is a polysome
A polysome consist of a **cluster of ribosomes** that are held, simultaneously by a strand of messenger RNA (mRNA) in rosette or helical group. They contain a **portion of the genetic code that each ribosome is translating** and are used in formation of multiple copies of same polypeptide
38
process of dna replication
the opening of the double helix and separation of the DNA strands, the priming of the template strand, and the assembly of the new DNA segment - lagging strand done in segments
39
how is the base sequence of dna transcribed into rna
Transcription begins when **RNA polymerase** binds to a promoter sequence near the beginning of a gene (directly or through helper proteins). RNA polymerase uses one of the DNA strands (the template strand) as a **template** to make a new, complementary RNA molecule. Transcription ends in a process called termination. Termination depends on sequences in the RNA, which signal that the transcript is finished.
39
how is the base sequence of dna transcribed into rna
Transcription begins when **RNA polymerase** binds to a promoter sequence near the beginning of a gene (directly or through helper proteins). RNA polymerase uses one of the DNA strands (the template strand) as a **template** to make a new, complementary RNA molecule. Transcription ends in a process called termination. Termination depends on sequences in the RNA, which signal that the transcript is finished.
40
post-transcriptional processing of rna
splicing of exons (different orders allows for diff proteins to be expressed/diff folding (shape) and function)
41
translation of mRNA
mRNA travels to ribosomes where rRNA reads codons on sequence of nucleotide bases and instructs tRNA to "grab" AA accordingly. tRNA brings AA and they are joint together into primary protein structure
42
key enzyme used in dna replication
DNA poolymerase, adds complementary bases in 5' to 3' direction
43
role of DNA polymerase
responsible for the process of **DNA replication**, during which a double-stranded DNA molecule is **copied** into two identical DNA molecules