Test 1 Flashcards
1
Q
What is the role of the nucleus?
A
Contain genetic info as chromatin
2
Q
Describe the structure of the nucleus
A
double membrane
nuclear pores
nucleolus
3
Q
What is the nucleolus?
A
Dense area where ribosomes are made
4
Q
What is chromatin?
A
DNA wrapped around histones
5
Q
Describe the structure of mitochondria
A
Double membrane
Inner membrane folded into cristae
Matrix
6
Q
What is the role of smooth ER?
A
Synthesis of lipid and hormones
7
Q
What is the role of rough ER?
A
Synthesis of membrane bound or secreted proteins
8
Q
What is the role of Golgi?
A
Modification and packaging of proteins
9
Q
Describe the secretory pathway
A
1 - rER: Aa’s to proteins, folded to form tertiary structure & glycosylation
2 - packaged into vesicles and transported to Golgi
3 - Golgi: vesicles fuses & proteins modified
4 - proteins packaged into secretory vesicles and fuse with cell surface membrane
10
Q
Which 8 organelles are found in prokaryotes?
A
Circular DNA, cell wall, pili, flagellum, food granules, mesosome, plasmid, capsule
11
Q
Differences between prokaryotes and eukaryotes (4)
A
1 - prokaryotes have no nucleus
2 - P have circular DNA, E have linear
3 - P have 70s ribosome , E have 80s
4 - P non membrane bound
12
Q
How does a protein’s secondary structure form?
A
Hydrogen bonds between peptides
13
Q
What is a beta pleated sheet?
A
Polypeptide chains zig zag forming sheet of antiparallel strands
14
Q
How do tertiary structures fold?
A
Bonds between R groups on amino acids
15
Q
Describe the structure of a cell membrane
A
- phospholipid bilayer
- selectively permeable
- hydrophilic phosphate head on outside, hydrophobic fatty acid inside
- transmembrane, integral and peripheral proteins
- glycoproteins & glycolipids
- cholesterol
16
Q
How can membrane fluidity be increased?
A
Unsaturated fatty acids so phospholipids less tightly packed
17
Q
How can membrane fluidity by decreased?
A
More cholesterol
18
Q
What is facilitated diffusion?
A
High conc to low conc via carrier or channel protein across a membrane
19
Q
What molecules use a carrier protein?
A
Large molecules such as glucose and amino acids
20
Q
What molecules use channel proteins?
A
Polar molecules such as ions
21
Q
What is osmosis?
A
Net movement of water from high water pot to low water pot across a selectively permeable membrane
22
Q
What is active transport?
A
Movement from low conc to high conc via carrier proteins across a membrane using energy from ATP
23
Q
What is bulk transport?
A
Energy dependent transport of molecules in and out of cells
24
Q
Compare globular and fibrous proteins
A
1 - chain of AA’s held by peptide bonds
2 - secondary structure held by hydrogen bonds
25
Contrast globular and fibrous proteins
1 - Globular has tertiary structure, fibrous doesn't
2 - G has hydrophilic groups outside, F has hydrophobic groups outside
3 - G is spherical and compact, F is long chains
26
What happens in the G1 phase?
Main growth, high metabolic activity depending on nutrient supply and temp
27
What happens in the S phase?
Cell replication and repair
28
What happens in the M phase?
Cell divides and 2 genetically identical diploid cells produced
29
Why is mitosis needed?
Growth (new cells) and repair (replacing)
30
What is the estimated average requirement? (EAR)
energy intake which meets needs of 50% of people
31
What is the lower reference nutrient intake (LRNI)?
energy intake which meets needs of only 2.5% of people
32
What is the higher reference nutrient intake? (HRNI)
energy intake which meets needs of 97.5% of people (GDA)
33
What is SDA (specific dynamic action)?
energy expended for metabolising food (eating, digestion and absorption)
34
Describe atherosclerosis
1 - endothelial damage due to high Bp/toxins
2 - inflammatory response: WBCs deposit cholesterol, forming atheroma
3 - Ca2+ and fibrous tissue build up forming plaque
4 - RAISED BP as artery narrows
35
Why does atherosclerosis lead to CVD?
Reduced flow to cardiac muscle
| increased risk of blood clots, blocking O2 supply
36
How does blood clotting lead to CVD?
Plaque in vessel ruptures, clotting occurs when thromboplastin is released by platelets
Blood supply is blocked
Heart is ischaemic
37
How do antioxidants prevent CVD?
prevent oxidation of LDL by providing electrons for free radicals
38
How do ACE inhibitors reduce the risk of CVD?
antihypertensive which reduces synthesis of angiotensin II, which causes vasoconstriction of vessels
39
How do calcium channel blockers control blood pressure?
antihypertensive
blocks calcium channels in muscle cells and artery lining
prevents contraction of muscle and constriction of blood vessel due to lack of calcium
40
How do diuretics control blood pressure?
increase urine volume so gets rid of excess fluids, reducing plasma volume and BP
41
How do statins control blood pressure?
inhibit enzyme in production of LDL by liver, decreasing cholesterol and CVD risk
42
How do anticoagulants control blood pressure?
- interferes with production of Vit K and affects synthesis of clotting factors
- reduced risk of thrombus blocking blood vessel
43
How do platelet inhibitors control blood pressure?
reduces stickiness of platelets and likelihood of clot formation
44
How can diet reduce the risk of CVD?
Reduce saturated fat and cholesterol consumption
Polyunsaturated fats
Reduce salt
More fruit and veg (vit e & c)
45
What side effects are associated with CVD drugs?
Dizziness, nausea, muscle cramps, kidney failure
46
What is succession?
A series of changes of organisms replacing each other over time
47
What is primary succession?
succession on inorganic surface devoid of any vegetation (bare rock, sand, etc.)
48
Describe the stages of primary succession
1 - pioneer species arrive and break down rock into soil
2 - intermediate species outcompete previous species and establish soil & root systems
3 - climax community: dominant species, biodiversity increases
49
What is secondary succession?
development of an ecosystem from existing soil that has been cleared of vegetation
50
How is secondary succession different to primary succession?
faster appearance of species because soil is already present, with minerals and microorganisms & there are already dormant seeds in the soil
51
Define climax community and explain why it’s stable
- final stage of succession, where there is one dominant species
- stable because there’s a balanced EQM of species
52
Nitrate deficiency
In amino acids, chlorophyll, DNA, ATP
| Stunted growth, yellow leaves
53
Magnesium deficiency
In chlorophyll
| Yellow leaves
54
Phosphorus deficiency
In DNA and ATP
| purple leaves, stunted growth
55
Calcium deficiency
```
Cell wall and membrane permeability
stunted growth (leaf margins)
```
56
Define ecosystem
A self-sustaining life-supporting environment with biotic and abiotic factors
57
Define population
All of the organisms of a particular species living in a particular habitat at a particular time
58
Define community
All of the populations of different species living in a particular habitat at a particular time
59
Define niche
The role of an organism in the ecosystem
60
Explain the niche of a plant
producer, so it produces food for other organisms
improves soil structure
provides shelter for organisms
61
What is deflected succession?
A community kept stable by human activity which prevents succession from running its course
62
How does intraspecific competition affect population?
1 - population increases when resources are plentiful
2 - eventually the resources will be limited so population declines
3 - smaller population less competition
63
What is carrying capacity?
The maximum stable population size of a species that an ecosystem can support
64
How does predation affect population?
1 - prey population increases, more food for predators so predator population increases
2 - prey population falls
3 - less food for predators, predator pop decreases
65
How are frame quadrats used for sampling?
Immobile populations
- measure off two areas of the same size
- random number generator to select coordinates
- number of organisms / percentage cover
- several sample sites used
- collect data in table
66
How are transects used for sampling?
Investigating distribution of populations
- measure off two areas of the same size
- collect data along transect using fram quadrats next to each other
- repeat
67
Describe the structure of chlorophyll a and b
- hydrophilic head due to Mg2+ at centre of porphyrin ring
| - hydrophobic tail due to hydrocarbon chain which anchors molecule into chloroplast membrane
68
Describe the structure and function of carotenoids
- hydrophobic
| - assist chlorophyll a+b by passing light to them (accessory pigments)
69
What light wavelengths do PS pigments absorb?
- all absorb blue light
| - carotenoids don’t absorb yellow to red
70
What is the role of the outer membrane of a chloroplast?
allows passage of CO2, O2 and H2O
71
What is the role of the inner membrane of a chloroplast?
Contains transporter proteins
72
What is the role of the thylakoid membrane?
LDR happens here
| contains photosynthetic pigments
73
What is the role of the stroma?
LIRs happen here
74
What is the role of the DNA loop in chloroplast?
DNA coding for proteins and enzymes
75
What happens in the light dependent reaction?
1. PS II P680 emits 2 excited e's, which pass to acceptor which is reduced
2. E's lost replaced by photolysis of H2O
3. E's pass to a series of carriers along electron transport chain and each is reduced and oxidised
4. Energy released as each carrier has a lower E level than the one before (synthesises ATP by photophosphorylation)
5. PSI P700 emits 2 e's and replaced by e's from transport chain
6. E's captured by an e acceptor and passed down chain
7. 2e's combine with H+ to reduce NADP+ to NADPH and H+
76
What happens in the Calvin cycle?
- CO2 fixation: CO2 combines with RuBP to form 2 GP
- Reduction: GP reduced to form GALP
- Regeneration of RuBP: GALP resynthesises 6 RuBP and produces 1 glucose
77
Define primary productivity
Rate at which energy is incorporated into organic molecules by plants
78
How is energy lost in food chains?
```
Not useful wavelength
Light transmitted through leaf
Used for transpiration
Used in respiration
Lost in faeces
```
79
What is net primary productivity?
The rate at which energy is incorporated into organic molecules that make up new biomass
80
What is secondary productivity?
Rate at which energy is used to make new consumer biomass
81
Describe the greenhouse effect
1. Short wavelength solar radiation passes through atmosphere
2. Some radiation absorbed, warming the Earth
3. Some longer IR radiation reflected off the Earth's surface
4. Longer wavelength IR absorbed by greenhouse gases, increasing the Earth's temperature
82
What are the stages of aerobic respiration and where do they take place?
1. Glycolysis (cytoplasm)
2. Link Reaction (matrix)
3. Krebs Cycle (matrix)
4. Electron transfer chain (inner membrane)
83
What happens during glycolysis?
1 - Phosphorylation of glucose: 2ATP added to form 2GALP + 2ATP
2 - GALP oxidised forming 2 pyruvate
NAD becomes reduced
84
What happens in the link reaction?
1 - pyruvate decarboxylated & oxidised to form CO2 and reduced NAD & acetate
2 - acetate combined with coenzyme A to form acetyl-coA
(2x per glucose)
85
What happens in the Krebs cycle?
1 - acetyl-coA combines with oxaloacetate to form citrate
2 - decarboxylation & oxidation 6C to 5C
3 - 5C to 4C
4 - ATP from substrate level phosphorylation
86
What happens in the electron transfer chain?
1 - H released from reduced NAD and FAD
2 - H split up into H+ and e-
3 - e- move down ETC, energy used to pump H+ matrix producing e-chem gradient
4 - chemiosmosis: H+ move down gradient via ATP synthase, producing ATP
5 - O2 is final e acceptor
87
Define chemiosmosis
Movement of H+ across a selectively permeable membrane, down an electrochemical gradient
88
How much ATP is made in aerobic respiration?
38, but really 30 b/c energy cost for transporting pyruvate and ADP into mitochondria
89
What is oxidative phosphorylation?
Production of ATP where energy is released in the ETC to establish H+ gradient and power ATP synthase
90
How is rate of respiration measured?
Volume of O2 taken up over period of time (distance moved by fluid)
Respirometer
Potassium hydroxide absorbs CO2
Control tube
91
What are the stages of anaerobic respiration?
1 - glycolysis: glucose to pyruvate
2 - lactate by oxidising reduced NAD (in cytoplasm)
3 - NAD regenerated so glycolysis happens again
92
How is lactic acid broken down?
EPOC
1 - transport of lactic acid to liver to resynthesise into glucose
2 - lactic acid to pyruvate via Krebs cycle
93
How else can ATP be generated?
Stored in muscles
| ATP-PC system: phosphocreatine to creatine
94
How are granum adapted to their function?
1 - lots of thylakoid so large surface area
2 - chlorophyll in thylakoid to absorb light
3 - electron carriers to produce ATP
