Wrong Questions - B1 to B3 Flashcards
(86 cards)
1
Q
Why can a body cell not grow into an embryo?
A
- body cells lost ability to differentiate as many genes are already switched off
- only embroynic cells are totipotent
2
Q
Why does a runner need to keep breathing quickly after a run?
A
- used anaerobic respiration as couldn’t get enough oxygen
- caused lactic acid to build up
- thus she needs extra oxygen to remove the oxygen debt by breaking down the glucose and remove the lactic acid
3
Q
How can DNA mutations lead to cancer?
A
- mutations to DNA effects the base sequence of DNA
- bases may be added,deleted or changed
- changes the amino acid sequence so they are read differently
- amino acids determine how protein folds thus different shaped proteins produced
- this means that proteins such as enzymes can’t catalyse reactions any more
- changes in enzymes (e.g active site), can cause harmful changes to call processes
4
Q
How does DNA replication occur?
A
- DNA unzips through the enzyme DNA helicase
- then DNA polymerase adds free complementary nucleotides to the exposed bases on both strands (A - T and C-G)
- strands now twist into a double helix
5
Q
Describe the steps of mitosis
A
- nuclear membrane breaks
- chromosomes lines up in centre and pulled apart by spindle fibres
- nuclear membrane forms
6
Q
What is the point of sieve plates in plants?
A
- found in phloem
- allow movement on sucrose
7
Q
How do our eyes dilate?
A
- pupils dilate when radial muscles contact
- allows more light into the eye
- this is a reflex action
8
Q
What part of a kidney tubule is affected by ADH?
A
- increases permeability of kidney walls
- thus collecting ducts
9
Q
What is the cerebrum in charge of?
A
- controls motor function, movement and conscious activities
10
Q
Why is adrenaline applied to wounds?
A
- reduces blood flow to the skin
- causes vasoconstriction in the skin
- less blood is lost
11
Q
Where is progesterone made?
A
- corpus luteum
12
Q
Why is photosynthesis important in the rate of transpiration?
A
- photosynthesis happens in the guard cells not epidermal cells, thus sugars are found in the guard cells (less sugar)
- epidermal cells have higher w.p than guard cells and allows water to move into guard cells by osmosis
- more turgid = open stomata due to thicker inner cell wall
- opening of stomata affects the transpiration rate
13
Q
Why is the rate of reaction very slow at 20 degrees?
A
- particles have less kinetic energy
- particles move slower
- less frequent collisions
14
Q
How can you check colour change more accurately?
A
- with a colorimeter
- get same person to judge the colour change
15
Q
Why is using a gas syringe more accurate?
A
- more accurate as otherwise the bubbles might be diff sizes or chance of missing it
- instead gas syringe collects the total volume of gas
16
Q
Why is calculating percentage change useful with osmosis practicals?
A
- you can still compare even if the sizes are different shapes
17
Q
What is the purpose of the cell membrane?
A
- it controls what leaves and enters the cell
- has receptor molecules that allow cells to communicate
18
Q
What is the purpose of the vacuole?
A
- it contains cell sap - a solution of salt and sugar
- it keeps the cell rigid and upright
19
Q
What is the purpose of the cell wall?
A
- it is made of cellulose
- it supports the cell and keeps the cell walls rigid
20
Q
Why do we use stains?
A
- it creates contrast to help us see subcellular structures
21
Q
Why is a higher magnification bad?
A
- makes it harder to focus
- harder to see the whole organism
22
Q
How is DNA arranged?
A
- arranged in chromosomes and divided into genes
23
Q
Describe enzyme-substrate complexes:
A
- enzymes are biological catalysts
- they are specific to a reaction - speed up reactions
- never used up
- bind at the active site to form E-S complexes
- products are released by the enzyme
24
Q
How do you test for non-reducing sugars?
e.g. sucrose
A
- add dilute HCl at 75 degrees C in a water bath
- add sodium- hydrogen carbonate
- add benedict’s reagent
- if blue = no sugar but red = yes
25
How do you test for proteins?
- Biuret test:
- add NaOH
- add CuSO4
- If blue = no protein but purple = yes
26
What's the symbol for lactic acid?
2(C3H6O3)
27
How is starch broken down?
- broken down by carbohydrase in animals
| - broken down by amylase in plants
28
How is H2O2 broken down?
- by catalyse
| - found in potatoes
29
Why does photosynthesis allow organisms to do?
- increase their biomass
| - allows respiration as it releases oxygen
30
What are the advantages of being a multi called organism?
- can grow larger
| - can have specialised organs and tissues
31
What is a cardiac muscle?
- no nerve impulse is needed from the brain for the heart to contract
32
What are valves used for in the heart?
- prevents back flow from the atrium to the ventricle
| - stops oxygenated and deoxygenated blood from mixing
33
How are fat cells specialised?
- can expand to x1000
- store fat
- small nucleus
- small cytoplasm
34
Why are adult stem cells useful?
- can differentiate into some cells and can repair damage such as reverse paralysis or cure arthritis
- pluripotent
35
How are the lungs adapted to exchange?
- constant ventilation and good blood supply = higher cont gradient
- alveoli have a spherical shape = high SA
- thin walls = shorter distance for diffusion
- moist lining for dissolving gasses
36
What are the adaptions of plant exchange surfaces?
- broad leaves for high SA
- thin = less distance
- intercellular spaces for gas exchange
- lower leaves with stomata for CO2 and O2 change and water to escape in transpiration
- root hair cells = high SA to get H20 and mineral ions
37
What are the advantages of a double circulatory system?
- diffusion occurs quickly
- blood pumped at high Pa = more oxygen to cells a
- this maintains the body temp
38
Where does the body send blood to?
- organs and tissue
- body and brain
- except for the lungs, O2 diffuses out and CO2 diffuses into the blood
39
What are the features of arteries?
- oxygenated blood
- blood away from the heart at high Pa
- small lumen
- thick elastic muscular walls that contract and expand (pulse)
- collagen allows it not to burst under high Pa
40
What are the features of capillaries?
- exchange between blood and tissues/cells
- small lumen
- 1 cell thick = shorter distance = higher diffusion
- medium Pa
- semi-permeable wall allows it to supply O2 and diffuses out CO2
41
What type of muscle is the heart?
- myogenic muscle
- contracts without receiving nerve impulses from the brain
- thus needs lots of mitochondria
42
Where are vascular bundles found in leaves?
- form networks to support tissue
43
What are the features of xylem?
- made from dead cells = no lignin
- transport h2o and mineral ions
- lignin supports the outside
44
Where are sugars made from photosynthesis used?
- used in meristems to make new cells
- roots to store tissue
- is an energy store
45
How is water lost through stomata in the transpiration stream?
- in light = photosynthesis happens
- thus in the light, photosynthesis makes sugars in the guard cells
- guard cells have a low w.p
- epidermal cells (next to the guard cells) have a high w.p as no sugars are made there (as they have no chloroplasts)
- thus water moves into the guard cells by osmosis = turgor pressure = inner wall thicks and stomata 'opens'
- water moves out of leaves into the air due to steep cont gradient
- BUT in dark = less water loss as less sugar in G cells = high w.p and water moves out into the epidermal cells = flaccid and 'close' the stomata
46
What are the advantages of the transpiration stream?
- keeps plants cool
- allows plants to keep turgor pressure and stay rigid and stop wilting
- water for photosynthesis
- mineral ions also taken into the plant from the soil along with h20
47
What do eukaryotic cells have that prokaryotic don't?
- eukaryotic cells have mitochondria but prokaryotic cells don't have mitochondria
- they get energy other ways
48
What happens when you enter a dimly-lit room vs a very brightly-lit room?
- dimly lit = pupils dilate = circular muscles relax and radial muscles contract
- brightly lit = pupils constrict = circular muscles contract and radial muscles relax
49
What is the function of the brain?
- the brain processes all information by receptor cells about the internal and external changes in the environment and hormones to make a coordinated response
50
What are CT scans?
- X-rays of the inside of the brain are compared for odd behaviour
- disadvantages = risk of cancer and can't see the brain
- advantages = can see 3D structures and need no surgery (thus less chance of infection and damage)
51
What is negative feedback?
- type of control mechanism in homeostasis
52
How does the cycle of the menstrual cycle begin again?
- if pregnant = high progesterone levels, thus uterus lining maintained and high progesterone inhibits FSH and LH
- if not pregnant = low progesterone levels and thus uterus lining sheds (menstruation) and low progesterone stimulates the production of FSH and LH
53
How does the kidney absorb necessary molecules from the blood?
Ultrafiltration:
- blood enters the kidney through the renal artery leading to the glomerulus
- high Pa due to narrow blood vessels leads small molecules to pass out of glomerulus to the Bowman's Capsule
- larger molecules remain in the blood
Selective Reabsorption:
- filtrate passes through the kidney tubule
- glucose, salts and water absorbed
- passes through Loop of Henle and collecting ducts
- extra water and salts are reabsorbed and waste is sent to the bladder for excretion
54
What is the cerebrum, cerebellum and medulla in charge of?
Cerebrum:
- consciousness, intelligence, memory, language
Cerebellum:
- balance, muscle coordination
Medulla:
- unconscious activities (breathing, the beating of the heart)
55
What is oxygen debt?
- the amount of oxygen needed if all the energy
| released was from aerobic respiration (1)
56
What chemical is released in the body after an organism starts respiring anaerobically?
- lactic acid
- produced during exercise (because of anaerobic
respiration) and removed after exercise / when
resting (1)
57
Who would produce more urine? Someone, who drank isotonic drinks after (Sanchez) a run or someone who drank just water after a run (Leroy)?
- Leroy produces more urine
- as this dilutes his blood more than Sanchez’s
- high water level is detected by the hypothalamus
- less ADH released from the pituitary gland
- decreases the permeability of the nephron/kidney
- less water reabsorbed (in kidney tubules)
- produces urine that is more dilute
58
How could it be tested if the spring is behaving elastically with only one mass?
- remove mass
| - check if it's still the same - has it deformed?
59
How can lower frequency waves be made with a spring?
- add masses
| - use spring with smaller spring constant
60
What are the reasons for higher anomalous results for spring oscillations in 10 seconds?
- timed too many oscillations
| - misread stopwatch
61
What is the minimum number of atoms in a molecule?
- 2, because you cannot have a molecule with only one atom, as this is an atom.
62
Why is foil used on a test tube in a photosynthesis experiment?
- foil doesn't allow light through
| - this causes the rate of photosynthesis to be 0
63
What happens to the CO2 concentration in someone's blood if their rate of respiration increases?
- concentration in blood increases
| - as CO2 is a product of respiration
64
Where are the glomerulus and Bowman's Capsule found?
- glomerulus- renal cortex
| - Bowman's Capsule - renal cortex
65
Where are the Loop of Henle and collecting ducts found?
- Loop of Henle - renal cortex, dips into the medulla, then renal cortex again
- collecting ducts - medulla
66
Describe hormonal methods of contraception:
- progesterone + oestrogen pill = o inhibits FSH and thickens cervical mucus and thins uterus lining so egg can't implant and prevents ovulation
- patch/ injection/ implant release o and p
- IUD = releases progesterone
67
Describe non-hormonal methods of contraception:
- IUS = kills sperms through a copper coil
- diaphragm = covers cervix (only works with spermicide)
- condom = barrier (prevents against STIs)
68
Resolution is...
- measure of the smallest object using an instrument
| - resolution is the ability to distinguish two objects from each other.
69
Give two advantages and disadvantages of CT scans?
Advantages:
No surgical operation is required –- so reduced risk of infection / brain damage.
Allows 3D structures to be seen – enabling accurate identification of abnormalities.
Other acceptable suggestions with explanation.
Disadvantages:
Requires use of several X-rays – which have the potential to cause cancer.
Only still images produced – cannot see brain functioning, so cannot always link problem
to source.
70
What is negative feedback?
- detecting a change
| - reversing that change
71
What causes red-green colourblindness?
- genetics
| - missing cones
72
Why might a scientist publish his work?
- to inform other scientists (who might be
working on the topic)
- to see if other scientists can replicate the
work/ to have it peer-reviewed
- to allow recognition for their work✓
73
How do you add an air bubble to a capillary tube?
- lift the end of the capillary tube out of the (beaker) of
water
- after a short time / when some air has gone in, put it back into the water
74
What happens when a cell doesn't have enzymes or a cell wall?
- cannot digest food
- cannot release energy
- cannot carry out any other
- named vital cell process
- cell cannot grow
- cell cannot reproduce
75
What effect does blocking ADH have?
- blocking ADH makes the kidney tubule less
permeable/less water reabsorbed
- blocking ADH increases the volume of water lost
from the body/present in urine/urine becomes
more dilute
- blood concentration is increased / water potential
lowered / water would move out of cell/water will
not move into cells
- eventually, blood and cells are isotonic/same
concentration/same water potential/same sodium
ion concentration
76
What is tRNA?
- tRNA is a carrier molecule for amino acids / tRNA/carrier molecule brings (correct) amino acids into
place / tRNA reads the triplets on the mRNA
77
What is our cerebellum in charge of?
- coordinate voluntary muscle movements
| - maintain posture, balance, and equilibrium
78
What is oxygen debt?
- quantity of oxygen required to break down lactic acid in anaerobic respiration
79
Where are mitochondria involved in making enzymes?
- provide energy for translation in ribosomes
80
What is the function of carbohydrates?
- energy for the body
| - fat oxidation
81
What are the two types of lipids?
- fats and oils
82
What is a gene?
- Section of DNA that codes for a characteristic
83
Difference between animal and plant stem cells:
· Animal stem cells usually differentiate at the early stages of their life
· Stem cells in adult animals are mainly used for replacement or repair
· Plant cells differentiate throughout their life cycle
· Plant stem cells are grouped together in structures called meristems
84
What is the medulla oblongata in charge of?
- automatic actions such as heart and breathing rate
85
What is the cerebrum in charge of?
- complex behaviour such as memory, language and personality
86
What components of the blood transport what molecules?
```
Molecules carried
Oxygen/haemoglobin ( by red blood cell)
Carbon dioxide (by plasma/rbc)
Glucose/amino acids (plasma)
Hormones (plasma)
urea (plasma)
water (plasma)
Antibodies (plasma)
```
