Cel 1 flashcards

Question 1

what is the genome

Answer 1

the complete set of genes in a cell

Question 2

what is the proteome

Answer 2

the full range of proteins a cell is able to produce

Question 3

describe the structure of mRNA

Answer 3

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

Question 4

what are codons

Answer 4

sequence of 3 bases in mRNA.

Question 5

what is the structure of tRNA

Answer 5

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

Question 6

what is the function of trna

Answer 6

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

Question 7

what is transcription

Answer 7

the production of mRNA from DNA

Question 8

what is the role of RNA polymerase

Answer 8

joining mRNA nucleotides

Question 9

how does transcription result in prokaryotes

Answer 9

directly in the production of mRNA from DNA

Question 10

how does transcription result in eukaryotes

Answer 10

the production of premNA which is then spliced to form mRNA

Question 11

What is translation

Answer 11

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

Question 12

describe transcription

Answer 12

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

Question 13

what is splicing

Answer 13

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

Question 14

describe translation

Answer 14

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

Question 15

what is the function of cartilage

Answer 15

supports and stops trachea and bronchi collapsing

Question 16

what is the function of elastic fibres

Answer 16

stretch and recoil

Question 17

what is the function of smooth muscle

Answer 17

contract and relax

Question 18

what is the function of goblet cells

Answer 18

produce mucus to trap pathogens

Question 19

what is the function of cilliated cells

Answer 19

sweeps mucus up

Question 20

what is the essential feature of alveolar epithelium

Answer 20

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

Question 21

what is ventilation

Answer 21

the movement of air in and out of lungs

Question 22

what kind of process is inspiration

Answer 22

active process because ATP is required

Question 23

describe inspiration

Answer 23

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

Question 24

what kind of process is expiration

Answer 24

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

Question 25

describe expiration

Answer 25

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

Question 26

describe pathway taken by oxygen molecule from an alveolus to blood

Answer 26

across alveolar epithelium and then capillary endothelium

Question 27

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

Answer 27

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.

Question 28

what is haemoglobin

Answer 28

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

Question 29

what is the function of haemoglobin

Answer 29

transpports by binding and releasing it

Question 30

explain the shape of the oxygen dissociation curve

Answer 30

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

Question 31

what is the bohr effect

Answer 31

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

Question 32

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

Answer 32

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

Question 33

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

Answer 33

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

Question 34

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

Answer 34

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

Question 35

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

Answer 35

Hb has a lower affinity and therefore dissociates more readily

Question 36

how is DNA in prokaryotic cells

Answer 36

short, circular and not associated with proteins

Question 37

how is DNA in eukaryotic cells

Answer 37

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

Question 38

what is a gene

Answer 38

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)

Question 39

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

Answer 39

4 to the power of the base

Question 40

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

Answer 40

3:1

Question 41

what is the ratio for amino acids to bases

Answer 41

number of amino acids x3

Question 42

why is genetic code described as universal

Answer 42

all organisms have DNA

Question 43

why is genetic code described as non-overlapping

Answer 43

each base is in only one base triplet

Question 44

why is genetic code described as triplet code

Answer 44

groups of 3 bases code for one amino acid

Question 45

why is genetic code described as degenerate

Answer 45

each amino acid has at least one triplet code

Question 46

what happens to remaining 44 bases (degeneracy)

Answer 46

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