unit 2 Flashcards
(114 cards)
1
Q
Define cell metabolism
A
total set of reactions in a cell
2
Q
What are metabolic pathways (+ other info)
A
series of enzyme catalysed reactions within a cell
- integrated meaning diff pathways are inter linked
- may have reversible and irreversible steps
3
Q
Define anabolic reactions
A
synthesis reactions that build up small molecules into large molecules and require energy
4
Q
Define catabolic reactions
A
degradation reactions that break down large molecules into smaller molecules and release energy
5
Q
How do membranes allow molecules through
A
Protein pore allow or restrict the passage of molecules through the membrane
6
Q
What are protein pumps
A
move molecules across the membrane and require energy to do this
7
Q
What do enzymes in membranes do
A
catalys specific biochemical reactions
8
Q
How can metabloc reactions be controlled
A
by the presence or absence of enzymes
or the regulation of key enzyme activity
9
Q
Define induced fit
A
how the active site of enzyme may change shape to better fit the substrate as the substrate binds
10
Q
Describe enzymes affect on activation energy
A
enzymes lower the activation energy
11
Q
Substrate molecules have a …. affinity for the ……. which means ….
A
high affinity for the active site meaning they bind readily
12
Q
Products have a …. affinity for the …. meaning ….
A
low affinity for the active site meaning they can leave the active site
13
Q
As substrate concentration increases …. but ….
A
the rate of reaction increases but will eventually become constant as it reaches its optimum rate
14
Q
How to change reversible reactions
A
the presence of substrate or removal of product can drive a sequence of reactions in a particular direction
15
Q
What do competitive inhibitors do
A
bind to an active site preventing the substrate from binding
16
Q
How can competitive inhibition be reversed
A
increasing the substrate concentration
17
Q
What do non competitive inhibitors do
A
bind away from the active site which has an effect of changing the shape of the active site preventing the substrate from binding
18
Q
When does feedback inhibition occur
A
this occurs when the end product of a metabolic pathway reaches a critical concentration
19
Q
Define feedback inhibition
A
where the end product inhibits an earlier enzyme in a metabolic pathway which prevents further synthesis of the end product
20
Q
Define respiration
A
the breakdown of respiratory substrates to release energy in the form of ATP
21
Q
Define glycolysis
A
the breakdown of glucose to pyruvate in the cytoplasm
22
Q
What are the two phases of glycolysis
A
the energy investment phase and the and the energy pay off phase
23
Q
What happens in the energy investment phase
A
ATP is required to phosphorylate glucose and intermediates
24
Q
What does phosphorylation in the energy investment phase result in
A
the generation of more ATP in the energy pay off phase
25
What is the net gain of ATP in glycolysis
2
26
What is the end product in glycolysis
pyruvate
27
What happens in aerobic glycolysis
pyruvate is broken down into an acetyl group
28
What does acetyl combing with and form (respiration)
combines with coenzyme A to form acetyl coenzyme A
29
Where does the citric acid cycle take place
in the matrix of the mitochondria
30
What happens to the acetyl group after it combines with coenzyme A
combines with oxaloacetate to form citrate
31
What happens to citrate
it is gradually converted back into oxaloacetate in a series of enzyme controlled steps
32
What is produced/released in the citric acid cycle
produces ATP and releases carbon dioxide
33
What do dehydrogenase enzymes do
they remove hydrogen ions and electrons from intermediates and pass them to the coenzyme NAD to form NADH
34
What happens to hydrogen ions and electrons from NADH
passed to the electron transport chain
35
Where is the electron transport chain located
the inner mitochondrial membrane
36
What happens when electrons are passed along the electron transport chain
they release energy
37
What is the electron transport chain
a series of carrier proteins on the inner mitochondrial membrane
38
What does the energy released in the electron transport chain do
allows hydrogen ions to be pumped across the inner mitochondrial membrane into the space between the inner and outer mitochondrial membrane
39
How is ATP produced in the electron transport chain
the flow of hydrogen ions through the inner membrane portein ATP synthase
40
Describe the role of oxygen in respiration
oxygen is the final hydrogen/electron acceptor as it combines with the hydrogen ions and electrons to form water
41
What is fermentation
occurs in the cytoplasm at the lack of oxygen
42
Fermentation results in much ..... than aerobic respiration
much less ATP production
43
What happens to pyruvate in animal cells
it is converted into lactate
| this is a reversible reaction
44
What happens to pyruvate in plants and fungi
it is converted into ethanol and carbon dioxide
| this is an irreversible reaction
45
ATP is used to ...... which require energy
to transfer energy to processes which require energy
46
What cellular processes require energy
Protein synthesis, contraction of muscles, active transport, DNA replication and carbon fixation
47
Metabolic rates can be compared by .....
measuring oxygen consumption, carbon dioxide production or heat production
48
Oxygen consumption can be measured using ....
an oxygen probe
49
Carbon dioxide can be measured using ....
a carbon dioxide probe
50
Heat production can be measured using ....
a calorimeter
51
Organisms with high metabolic rates ....
require efficient delivery of oxygen to cells
52
Rate birds+mammals, reptiles+amphibians and fish by their metabolic rates (high to low)
birds and mammals -> reptiles and amphibians -> fish
53
What circulatory system do birds and mammals have + explain it
complete double circulatory system with two atria and two ventricles
54
What circulatory systems do amphibians and most reptiles have + explain it
incomplete double circulatory system with two atria and one ventricle
55
What circulatory system do fish have + explain it
single circulatory system with one atria and one ventricle
56
Why are complete double circulatory systems the most efficient
they enable higher metabolic rates by preventing the mixing oxygenated and deoxygenated blood
+
they also keep blood at high pressures allowing efficient oxygen delivery to cells
57
The metabolic rate of an organism is affected by ..... eg ....
abiotic factors eg temperature salinity and pH
58
The internal environment of conformers is dependent on .....
the external environment
59
How do conformers tolerate variations in the external environment
behavioural responses eg lizards basking in the sun
60
Define conformers abilities
low metabolic costs (do not require energy) and can only occupy a narrow range of ecological niches
61
The internal environment of regulators is ....
maintained regardless of the external environment
62
Regulators use metabolism to ....
control their internal environment eg water balance, temperature, blood sugar
63
Define homeostasis
the use of physiological mechanisms to maintain internal body conditions at optimum levels
64
Define regulators abilities
they expend energy (eg to migrate and avoid adverse conditions) and occupy a wider range of ecological niches
65
Define thermoregulation
the maintenance of a constant internal temperature
66
What is the temperature monitoring centre in the body
the hypothalamus
67
How does the hypothalamus recieve and send messages
recieves messages through nerve impulses from thermo-receptors in the skin and sends messages through nerve impulses to effectors
68
Define negative feedback control
uses corrective responses to revers changes in internal tempereature to return temperature to normal //or// a change in a factor triggers a mechanism which results in that factor returning to normal level (set point)
69
What are the 3 human responses to increase in body temperature/overheating
+ sweating - body heat is used to evaporate water in sweat thereby cooling the skin
+ vasodilation - increased blood flow to the skin increases heat loss by radiation
+ reduction in metabolic rate - to reduce heat production
70
What are the 4 human responses to decrease in body temperature/overcooling
+ shivering - rapid involuntary muscle contraction generates heat
+ vasoconstriction - decreased blood flow to the skin decreases heat loss by radiation
+ contraction of hair erector muscles - traps a layer of insulating air
+ increase in metabolic rate - to produce more heat
71
Why is maintenance of body temperature required + what does it ensure
for optimal enzyme activity
| ensures high diffusion rates required to maintain metabolism
72
Regulators are unable to maintain their internal environment when ....
when the external environment varies beyond tolerable limits for normal metabolic activity
73
Define dormancy
part of a lifecycle allowing survival during conditions when the energy costs of metabolic activity would be too high
74
During dormancy the metabolic rate .....
is reduced to save energy
75
Define predictive dormancy
occurs before the onset of adverse conditions
76
Define consequential dormancy
occurs after the onset of adverse conditions
77
How do some animals survive low winter temperatures
hibernation
78
How do some organisms survive high temperatures/drought
aestivation
79
Define daily torpor
when some animals with high metabolic rates can temporarily reduce their metabolic rate eg hummingbirds
80
Why do animals migrate/what is migration
migration involves relocating to an area with more suitable environmental conditions
uses energy to avoid adverse conditions
81
What is innate behaviour
behaviour that is inherited (migration can be this)
82
What is learned behaviour
behaviour that parents teach/is developed as a result of experience (migration can be this)
83
How can migration be tracked
radio/satellite tracking, marking, radar and sonar
84
Micro-organisms include ....
archea, bacteria and some eukaryotes
85
Micro-organisms use .... and produce ....
microorganisms use a wide variety of substrates for metabolism and produce a range of products from their metabolic pathways
86
Describe micro-organisms growth media
contains raw materials for biosynthesis and an energy source
87
Some microorganisms produce their own .... and some require ....
produce their own complex molecules for biosynthesis (e.g amino acids vitamins and fatty acids) and some require complex molecules in the growth medium
88
Where is the energy source for a microorganism derived from
from a chemical substrate or from light in photosynthetic micro organisms
89
How is a fermenter used in the culture of micro organisms
- provides optimum conditions through control of temp, oxygen level and pH
- provides sterile conditions to reduce competition for nutrients with unwanted microorganisms and reduces the risk of spoilage of the product
90
Examples of products produced in fermenters
antibiotics, enzymes, vaccines
91
What are the four phases of frowth and changes in culture conditions graph
lag
log
stationary
death
92
Explain the lag phase of the graph
enzymes are induced to metabolise substrates + cells adjust to conditions
93
Explain the log phase of the graph
rapid growth of micro-organisms due to plentiful nutrients / cells grow and multiply at maximum rate
94
Explain the stationary phase of the graph
due to nutrient depletion and toxic metabolites begin to accumulate / number of cells dying is equal to number of cells produced
95
Explain the death phase of the graph
due to toxic metabolites accumulation and lack of nutrients / number of cells dying exceeds number being produced
+ only viable cell count shows in this phase
96
Define secondary metabolites
produced in the stationary phase and may confer an ecological advantage in the wild by allowing the micro-organism to outcompete other species e.g antibiotics
97
Define viable cell count
only the living cells
98
Define total cell count
both living and dead cells
99
What does mutagenesis of recombinant DNA technology do?
improve wild strains of micro organisms
100
Define mutagenesis
the creation of mutations and can be achieved using mutagenic agents e.g. uv light, x-rays and gamma rays, mustard gas
101
Exposure of microorganisms to mutagenic agents results in ...
mutations which may produce an improved strain of micro organism e.g. give an increased yield of product
102
What is recombinant dna technology
describes taking a gene from an organism and transferring it into a micro organism to enable the micro organism to produce plant or animal proteins
103
What is a vector (DNA)
a DNA molecule used to carry foreign genetic material into another cell e.g. plasmids and artificial chromosomes
104
When are artificial chromosomes preferable over plasmids as vectors
when larger fragments of DNA are required to be inserted
105
What are restriction endonuclease enzymes used for
recognising specific nucleotide base sequences and cutting specific genes out at those sequences leaving sticky ends
+
recognising specific nucleotide base sequences and cutting open plasmids at those sequences
106
How are complementary sticky ends produced
when the same restriction endonuclease is used to cut open the plasmid and cut out the gene from the chromosome
107
How are complementary DNA sequences sealed into place
DNA ligase enzymes
108
What do recombinant plasmids and artificial chromosomes contain
restriction sites, regulatory sequences, an origin of replication and selectable markers
109
Restriction sites contain ....
target sequences of DNA where specific endonucleases cut
110
What do regulatory sequences do
controls gene expression
111
What does the origin of replication do
allows self replication of the plasmid/artificial chromosome
112
What do selectable marker genes do
ensure that only microorganisms that have taken up the vector grow in the presence of the selective agent eg antibiotic resistance genes
113
Genes may be introduced to a genetically engineered micro-organisms genome to ....
to prevent its survival in the external environment as a safety mechanism
114
Recombinant yeast cells may be used instead of bacteria because ....
bacteria may be unable to produce an active form of protein due to an inability to correctly fold polypeptides
