Cel 1 flashcards

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1
Q

what is the genome

A

the complete set of genes in a cell

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2
Q

what is the proteome

A

the full range of proteins a cell is able to produce

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3
Q

describe the structure of mRNA

A

carries nucleotide message fom DNA to ribosome. Linear and single stranded because carries message of one patricular gene. length of the gene. has codons.

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4
Q

what are codons

A

sequence of 3 bases in mRNA.

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5
Q

what is the structure of tRNA

A

clove leaf shaped. 80 nucleotides in size and has anticodons.

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6
Q

what is the function of trna

A

carries specific amino acids to mrna and ribosome so amino acid can be put together in order dictated to ribosome by Mrna

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7
Q

what is transcription

A

the production of mRNA from DNA

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8
Q

what is the role of RNA polymerase

A

joining mRNA nucleotides

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9
Q

how does transcription result in prokaryotes

A

directly in the production of mRNA from DNA

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10
Q

how does transcription result in eukaryotes

A

the production of premNA which is then spliced to form mRNA

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11
Q

What is translation

A

the poduction of polypeptides from the sequence of codons carried by mRNA.

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12
Q

describe transcription

A
  1. DNA helicase unzips DNA breaking H bonds
  2. RNA polymerase enables binding of complementary activated RNA nucleotides (A,U,C,G) to template strands and forms bonds in sugar phosphate backbone
  3. mRNA synthesis when stop triplet reached on DNA
  4. In prokaryotes mRNA deataches from circular DNA and travels to ribosome in eukaryotes pre-mRNA spliced into mRNA
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13
Q

what is splicing

A

splicing removes introns and rejoins extrons which can be rejoined in different orders to create different proteins

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14
Q

describe translation

A
  1. ribosome binds to 2 codons of mRNA at start codon
  2. tRNAs, carrying specific amino acids and specific anticodons
  3. bind to complementary codons on mRNA
  4. ribosome forms peptide bond between amino acids
  5. ribosome moves along mRNA
  6. codon sequence determines amino acid order
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15
Q

what is the function of cartilage

A

supports and stops trachea and bronchi collapsing

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16
Q

what is the function of elastic fibres

A

stretch and recoil

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17
Q

what is the function of smooth muscle

A

contract and relax

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18
Q

what is the function of goblet cells

A

produce mucus to trap pathogens

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19
Q

what is the function of cilliated cells

A

sweeps mucus up

20
Q

what is the essential feature of alveolar epithelium

A

made up of squamous epithelial cells which are single, flat covering and 1 layer, which means there is a short diffusion pathway for gas exchange to occur

21
Q

what is ventilation

A

the movement of air in and out of lungs

22
Q

what kind of process is inspiration

A

active process because ATP is required

23
Q

describe inspiration

A
extenal intercostal muscles contract
therefore ribs move up and out
diaphram contracts and relaxes
thus lung volume increases
therefore air pressure decreases
therefore air flows in down air pressure gradient
24
Q

what kind of process is expiration

A

passive at rest- no ATP required because muscles relax

but active on exercise because internal intercostal muscles contract to expel a large amount of air

25
Q

describe expiration

A

external intercostal muscles relax therefore ribs move down and in
diaphram relaxes therefore domed/raised
thus lung volume decreases
therefore lung air pressure increases
therefore air flows out down air pressure gradient

26
Q

describe pathway taken by oxygen molecule from an alveolus to blood

A

across alveolar epithelium and then capillary endothelium

27
Q

describe how oxygen in air reaches capillaries surrounding alveoli in lungs (details of breathing not required)

A

as a result of mass transport (movement of air down a pressure gradient through a tube) air moves down the trachea, the bronchi and the bronchioles to alveoli. the oxygen in the air then diffuses across the alveolar epithelium and capillary endothelium to get to capillary.

28
Q

what is haemoglobin

A

a globular protein with a quaternary structure and each polypeptide chain has a haem prosthetic group

29
Q

what is the function of haemoglobin

A

transpports by binding and releasing it

30
Q

explain the shape of the oxygen dissociation curve

A

first oxygen binding changes tertiary structure therefore revealing next two binding sites which makes next two O2 molecules easy to bind to. The fourth O2 binding site is more difficult to bind to because 1/4 chance of binding to it therefore causing s shaped curve

31
Q

what is the bohr effect

A

concept that partial pressure of co2 as well as partial pressure of O2 affects O2 saturation of Hb

32
Q

what happens to oxygen dissociation curve when partial pressure of oxygen increases

A

haemoglobin has a decreased affinity for oxygen therefore dissociates more readily (shifts to right)

33
Q

what happens to oxygen dissociation curve when partial pressure of CO2 decreases

A

decreased partial pressure CO2 causes Hb affinity for oxygen to increase therefore oxygen dissociates more readily

34
Q

what happens to oxygen dissociation curve when an organism is in an oxygen poor environment

A

Hb has a higher affinity and therefore associates more readily so curve shifts to left

35
Q

what happens to oxygen dissociation curve when organism is more metabolically active

A

Hb has a lower affinity and therefore dissociates more readily

36
Q

how is DNA in prokaryotic cells

A

short, circular and not associated with proteins

37
Q

how is DNA in eukaryotic cells

A

DNA molecules are very long, linear, and associated with proteins called histones. Together a DNA molecule and its associated proteins form a chromosome.

38
Q

what is a gene

A

a gene is a base sequence of DNA that codes for the amino acid sequence of a polypeptide or functional RNA (including ribosomal RNA and tRNA)

39
Q

what is the maths for bases to amino acids (proving triplet code)

A

4 to the power of the base

40
Q

what is the ratio for number of bases coding for amino acids

A

3:1

41
Q

what is the ratio for amino acids to bases

A

number of amino acids x3

42
Q

why is genetic code described as universal

A

all organisms have DNA

43
Q

why is genetic code described as non-overlapping

A

each base is in only one base triplet

44
Q

why is genetic code described as triplet code

A

groups of 3 bases code for one amino acid

45
Q

why is genetic code described as degenerate

A

each amino acid has at least one triplet code

46
Q

what happens to remaining 44 bases (degeneracy)

A

several triplets code for 1 amino acid and some used as start/stop codons