unit 2 Flashcards
(160 cards)
1
Q
what is a metabolic pathway?
A
an integrated series of enzyme-controlled reactions
2
Q
what is metabolism?
A
all the reactions taking place within a cell
3
Q
catabolic
A
breakdown, releasing energy
4
Q
catabolic example
A
aerobic respiration
5
Q
anabolic
A
built up, requiring energy
6
Q
anabolic example
A
protein synthesis
7
Q
what types of steps are there in metabolic pathways?
A
reversible
irreversible
alternative routes
8
Q
what do irreversible and reversible steps in a metabolic pathway do?
A
allows the process to be kept under tight control
9
Q
what do alternative routes in a metabolic pathway do
A
allow steps to be bypassed
10
Q
what do inner membranes do?
A
enables metabolic activity to be localised
11
Q
examples of organelles that are membrane bound
A
mitochondria
chloroplast
12
Q
what makes up the membrane?
A
proteins
phospholipids
13
Q
types of proteins in the membrane
A
pores
pumps
enzymes
14
Q
what do pores in the membrane do?
A
allow diffusion of specific molecules across the membrane
15
Q
what do pumps in the membrane do?
A
transports molecules against the concentration gradient
16
Q
what do enzymes in the membrane do?
A
speed up the rate of biochemical reactions in the cell
17
Q
what is the activation energy?
A
minimum energy required by colliding particles to form an
activated complex
18
Q
what effect do enzymes have on activation energy?
A
lowers it
19
Q
what is an induced fit?
A
when the active site changes shape to better fit the substrate after the substrate binds
20
Q
what are the effects of an induced fit?
A
ensures the active site comes into close contact with the substrate molecules
increases the chance of a reaction taking place
21
Q
describe affinity during a reaction
A
substrates have high affinity for active site
products have low affinity for reaction site so they separate
22
Q
what does a competitive inhibitor do?
A
competes with the substrate for the available active site
23
Q
how do competitive inhibitors reduce the rate of reaction?
A
active sites are blocked so substrate molecule cannot bind
24
Q
effect of substrate concentration on competitive inhibition?
A
reverse the effect
25
what does a non-competitive inhibitor do?
does not combine directly with the active site on the enzyme
26
how does a non-competitive inhibitor reduce the rate of reaction?
changes the shape of the enzyme, indirectly changing the shape of the active site
prevents the substrate from binding
27
effect of substrate concentration on non-competitive inhibition?
cannot be reversed
28
feedback inhibition
As the concentration of an end product reaches a certain concentration, some of it binds to the enzyme earlier in the pathway, inhibiting this enzyme
This blocks the pathway and prevents further synthesis of the end product
29
what is the key role of ATP in cells?
transfer energy to cellular processes which require energy
muscle contractions
30
where does glycolysis take place?
cytoplasm
31
what stages of respiration require oxygen?
citric acid cycle
electron transport chain
32
what is ATP required for in glycolysis?
the phosphorylation og glucose
33
what does dehydrogenase do?
removes hydrogen ions and electrons from glucose
34
what enzyme carries hydrogen ions and electrons to stage 3?
NAD in the form NADH
35
where does the citric acid cycle take place?
matrix of the mitochondria
36
what is pyruvate converted into?
acetyl which combines with coenzymeA to form acetyl coenzymeA
37
how is citrate formed?
acetyl from acetyl coenzymeA combines with oxaloacetate
38
how is oxaloacetate regenerated?
Through a series of enzyme controlled reactions, citrate is converted back into oxaloacetate
39
what gas is released during the citric acid cycle?
carbon dioxide
40
where does dehydrogenase work?
glycolysis
citric acid cycle
41
where does the electron transport chain take place?
inner mitochondrial membrane
42
what is the electron transport chain?
a series of carrier proteins attached to the inner mitochondrial membrane
43
where do hydrogen ions and electrons get passed to?
the electron transport chain
44
role of electrons in the electron transport chain
electrons passed along the membrane releasing energy
45
what is the energy from electrons used for?
pumps hydrogen ions across the membrane
46
how is ATP generated in the electron transport chain?
the hydrogen ions flow back through the membrane through ATP synthase which generates ATP
47
what do the hydrogen ions do once they have flown through ATP synthase?
combine with the electrons and oxygen to form water
48
what is the final hydrogen acceptor?
oxygen
49
where does fermentation take place?
cytoplasm
50
when does fermentation take place?
if there is an absence of oxygen
51
what fermentation reaction is reversible?
animals
not yeast and plant
52
fermentation in animal cells
glucose - pyruvate - lactate
53
fermentation in yeast and plant cells
glucose - pyruvate - ethanol + carbon dioxide
54
what is metabolic rate?
The quantity of energy consumed by an organism per unit of time
55
what can metabolic rate be measured as?
The volume of oxygen consumed oer unit of time
The volume of carbon dioxide produced per unit of time
The heat produced per unit of time
56
what can metabolic rate be measured using?
Respirometer
Calorimeter
Carbon dioxide probe
Oxygen probe
57
how does a respirometer work?
CO2 produced by respiration is absorbed by a carbon dioxide absorption material
As oxygen is used up, the level of the liquid will rise
This is measured to see the volume of oxygen used per unit of time
58
metabolic rates from highest to lowest
Birds and mammals
Reptiles and amphibians
Fish
59
why do higher metabolic rates need a better circulatory system?
to allow efficient delivery of oxygen to their cells
60
what type of circulatory system do birds and mammals have?
complete double
61
what type of circulatory system do reptiles and amphibians have?
incomplete double
62
what type of circulatory system do fish have?
single
63
benefits of birds and mammals circulatory system?
no mixing of oxygenated and deoxygenated blood due to the septum in the ventricles
blood can be pumped at a higher pressure
64
features of birds and mammals circulatory system?
2 atria and ventricles
chambers separated by septum
blood moves through heart twice in each circuit
65
features of reptiles and amphibians circulatory system?
2 atria
1 ventricle
66
why is the circulatory system of reptiles and amphibians less efficient?
ventricle contains no septum so deoxygenated and oxygenated blood mixes
67
pressure of blood in a circulatory system of a fish
high pressure to gills
low pressure at capillaries
68
features of a fish circulatory system?
1 atrium and ventricle
blood only passes through the heart once in each circuit
69
example of abiotic factors that can affect an organisms ability to maintain its metabolic rate?
pH
salinity
temperature
69
what is a conformer?
organism whose internal environment is dependant on their external environment
69
how do conformers maintain optimum metabolic rate?
behavioural responses
70
example of a conformers behavioural response
lizard bask in the sun to absord heat energy
71
what do behavioural responses do for conformers?
Allows them to tolerate variation in their external environment
72
advantage to conformers
low metabolic costs so saves energy
73
how do regulators maintain their internal environment?
use negative feedback control
73
advantage to regulators?
Can live in a wide range of ecological niches
73
disadvantage to conformers
Narrow range of ecological niches as its less adaptable to environmental change
73
what is a regulator?
organisms who maintain their internal environment regardless of their external environment
74
disadvantage to regulators?
high metabolic costs
74
what is the process in homeostasis?
requires energy from metabolism
is controlled by negative feedback
is essential in thermoregulation
74
what is homeostasis?
where an organism maintains a constant internal environment irrespective of the external environment
75
what is negative feedback control?
used by regulators to achieve homeostasis
76
what makes up the negative feedback system?
set point
receptors
messages
effectors
77
what do receptors do?
detect the level of a factor
78
what do messages do?
sent if levels are too high/low
79
how are messages sent around the body?
electrical impulses are sent to the effectors through nerves
80
what is the hypothalamus?
temperature monitoring unit of your brain
81
what is thermoregulation?
the process of regulating temperature to maintain homeostasis
a type of negative feedback control
82
why is thermoregulation important?
optimal enzyme activity
high diffusion rates
83
what does the body do to cool down?
sweating
vasodilation
decrease metabolic rate
84
sweating
Body heat is used to evaporate water in the sweat cooling your skin
85
vasodilation
This is an increased blood flow to the skin which increases heat loss
86
decreasing metabolic rate
less heat produced
87
what does the body do in response to a decrease in temperature?
shiver
vasoconstriction
hair erector muscles contract
increase metabolic rate
88
shivering
Muscle contraction generates heat
89
vasoconstriction
This is a decreased blood flow to the skin which decreases heat loss
90
hair erector muscles contract
traps layer of insulating air
91
increased metabolic rate
more heat produced
92
surviving adverse conditions
dormancy
93
avoiding adverse conditions
migration
94
what is dormancy?
part of an organisms’ lifestyle to allow survival during a period of time when the costs of continued normal metabolic activity would be too high.
95
effect of dormancy
Metabolic rate
Heart rate
Breathing rate
Body temperature
96
two categories of dormancy?
predictive
consequential
97
positive to dormancy
animal avoids adverse conditions while spending minimal energy
98
predictive dormancy
occurs before the onset of adverse conditions
99
consequential dormancy
Occurs after the onset of adverse conditions
100
advantage to consequential dormancy
the organism can remain active for longer and take advantage of available resources
101
disadvantage to consequential dormancy
a sudden severe change in an abiotic factor may kill off many organisms before they become dormant
102
types of dormancy?
hibernation
aestivation
daily torpor
103
hibernation
survive during winter/low temperatures
104
aestivation
survive during drought/high temperatures
105
daily torpor
A daily period of reduced activity in some animals with high metabolic rates
106
what is mirgation?
avoids metabolic adversity by expending energy to relocate to a more suitable environment
107
advantage to migration
avoids metabolic adversity caused by low temperatures and shortage of food
108
disadvantage to migration
huge energy expenditure to get a more suitable environment
109
how do animals know to migrate?
innate or learned behaviour
110
what is innate behaviour?
inherited and instinctive
111
what is learned behaviour?
gained by previous migration or experience
112
what are specialised techniques used for?
used to study long-distance migration
113
types of specialised techniques
satellite tracking
leg rings
114
satellite tracking
emits signals which ic picked up by receivers
115
leg rings
if a bird is recaptures, the number on the bird is reported and where they found it to collect data
116
types of microorganisms
archaea
bacteria
some species of eukaryotes
117
why are microorganisms useful?
Adaptability
Ease of cultivation
Speed of growth
Produce useful products
Food substrate is often cheap
118
microorganism metabolism
use a wide variety of substrates and produce useful products
119
what does a growth medium require for the growth of microorganisms?
raw materials for biosynthesis
energy source
120
examples of raw materials for biosynthesis
vitamins
fatty acids
amino acids
121
how does the growth medium get an energy source?
from chemical substrates
from light in photosynthetic organisms
122
what are the ways that raw materials can be found in the growth medium?
many microorganisms produce them
others get them supplied
123
culture conditions
sterility
temperature
oxygen levels
pH
124
effects of sterility in growth media
Reduce competition with desired micro organisms for nutrients
Reduce the risk of spoilage of the product
125
why does temperature need to be monitored in growth media?
Keeps enzymes at their optimum temperature
126
why do oxygen levels need to be monitored in growth media?
Allows aerobic respiration to occur preventing fermentation
127
why does pH need to be monitored in growth media?
Keeps enzymes at their optimum pH
Buffer or the addition of acids can control this
128
phases of growth
lag
log/exponential
stationary
death
129
lag phase
enzymes are induced to metabolise substrates
130
log/exponential phase
Contains the most rapid growth of microorganisms due to plentiful nutrients
131
stationary phase
Nutrients in the culture media become depleted
Production of toxic metabolites
Secondary metabolites are also produced
132
example of a secondary metabolite produced?
antibiotic
133
what to secondary metabolites do?
These metabolites confer an ecological advantage by allowing the microorganisms which produce them to outcompete other microorganisms
134
death phase
Toxic accumulation of metabolites
Lack of nutrients in the culture
135
total cell count
The total number of cells present including live and dead cells
136
viable cell count
The total number of living cells present
137
advantage of viable cell count
shows the death phase where cell numbers are decreasing
138
how can wild strains of microorganisms be improved?
mutagenesis
recombinant DNA technology
139
what can result in mutations?
exposure to UV light
radiation
mutagenic chemicals
140
restriction endonuclease role
Cuts open plasmids and specific genes (restriction site) out of chromosomes leaving sticky ends
141
how are complementary sticky ends achieved?
when the same restriction endonuclease is used to cut open the plasmids and the gene
142
role of ligase
Seals the gene into the plasmid
Forms a recombinant plasmid containing recombinant DNA
143
what is a vector?
DNA molecule used to carry foreign genetic information into another cell
144
what is used as vectors in recombinant DNA technology?
Plasmids and artificial chromosomes
145
difference between plasmids and artificial chromosomes
artificial chromosomes are preferable as vectors when larger fragments of DNA is required to be inserted
146
what do plasmids and artificial chromosomes contain?
restriction site
regulatory sequence
origin of replication
selectable marker
147
restriction site
Target sequences of DNA where specific restriction endonuclease cut
148
regulatory sequence
Control gene expression of the vectors own gene and the inserted gene
149
origin of replication
Allows self-replication of the vector
150
2 advantages to a selectable marker
resistance to a selective agent that would normally kill it
ensures only the microorganism with the vector will grow in the presence of the selective agent
151
safety mechanism to growing microorganisms
genes are often introduced that prevent the survival of the microorganism in an external environment
152
what is the result of expressing plant or animal DNA in bacteria DNA?
polypeptide being folded incorrectly
153
