Don't Know Flashcards
(115 cards)
1
Q
What do chromosomes contain?
A
The genetic information that determines the structure and function of a cell.
2
Q
What is a chromosome?
A
A single strand of DNA
3
Q
What is DNA made up of?
A
a sequence of nucleic acids
4
Q
Define DNA:
A
a large biomolecule made up of a sequence of nucleic acids that forms a digital code for making a protein
5
Q
Describe the four steps in transcription:
A
- RNA polymerase binds to a region of non-coding DNA in the front of gene
- The two DNA strands unzip and the RNA polymerase moves along one of the strands of DNA
- It uses coding DNA in the gene as a template to make mRNA. Base pairing ensures the mRNA is complementary to gene
- mRNA then moves out of nucleus and joins up with ribosome in cytoplasm.
6
Q
Describe the 4 step process of translation:
A
- Amino acid are brought to ribosome by tRNA.
- The order in which the amino acids are brought to the ribosome matches the order of codons on mRNA
- Part of the tRNA’s structure called the anticodon is complementary to the codon for the amino acid ensuring the amino acids are brought to ribosome in correct order
- The amino acids are joined together making a protein.
7
Q
What are two features of asexual reproduction?
A
no variation, does not depend on production of gametes
8
Q
What are two features of sexual reproduction?
A
genetic variation, haploid gametes required
9
Q
What is mitosis used for?
A
growth, tissue repair and asexual reproduction
10
Q
What is meiosis used for?
A
to create haploid gametes
11
Q
Define genetic variation:
A
The differences in the sequence of bases of a gene between species or between individuals of the same species.
12
Q
What is genetic mutation?
A
The alteration of a sequence of bases in DNA that may or may not altar the amino acid sequence.
13
Q
What is the order of organisation in all living things?
A
Atom, molecule, macromolecule, organelle, cell, tissue, organ, organ system, organism
14
Q
Define organelle:
A
small part of cell that has specific function
15
Q
Define tissue:
A
Group of specialised cells that have the same function
16
Q
Define organ:
A
A group of tissues in a living organism that have adapted to carry out the same function
17
Q
Define organ system:
A
Group of organs that carry out specific functions
18
Q
Define osmosis:
A
The movement of water molecules from an area of high water potential to an area of low water potential across a semi-permeable membrane.
19
Q
What are two palisade cell adaptations?
A
located at top of leaf, lots of chloroplasts
20
Q
What is the function of stomach acid?
A
Kills bacteria and creates optimum Ph
21
Q
What is the function of bile?
A
Breaks down stomach acid and neutralises it. Also emulsifies fats to increase the SA.
22
Q
Function of mouth
A
mechanical digestion
23
Q
function of oesophagus
A
peristalsis
24
Q
function of salivary gland
A
produce saliva containing amylase
25
function of stomach
Muscular organ where chemical digestion occurs
26
function of pancreas
produces enzymes
27
function of liver
produces bile
28
function of gall bladder
stores bile
29
function of duodenum
where food is mixed with enzymes and bile
30
function of illeum
where digested food is absorbed into blood
31
function of colon
where water is reabsorbed
32
function of rectum
where faeces is stored
33
location and action of amylase
mouth + pancreas (breaks starch into maltose)
34
location and acton of maltase
small intestine (breaks down maltose into glucose)
35
location and action of protease
stomach + pancreas (breaks down protein into amino acids)
36
location and action of lipase
pancreas (breaks down lipids into fatty acids and glycerol)
37
What are three villi adaptations
large SA, thin walls, good blood supply
38
Define transpiration:
Water evaporation from the leaf causing the movement of water through the plant
39
What does the xylem transport?
water and dissolved minerals
40
What does the phloem transport?
sucrose and amino acids
41
Describe the six steps of the water pathway:
1. water from soil enters plant through root hair cells via osmosis
2. moves to root cortex cell via osmosis
3. moves to xylem via osmosis
4. water moves up xylem towards leaf via transpiration stream
5. water moves from xylem into mesophyll cells by osmosis
6. water evaporates into spades in spongey mesophyll layer, followed by diffusion of water vapour through stomata
42
what is the transpiration stream?
The removal of water from the leaf producing a tension from above creating a water potential gradient in the xylem drawing cohesive water molecules up the plant.
43
Define a hormone:
a chemical messenger that moves through the blood that changes the behaviour of another organ
44
what are the basic three steps of how hormones work?
released from gland, travel through blood to target cell, target cells change behaviour
45
function of testosterone:
stimulate growth of secondary characteristics
46
function of adrenaline:
stimulates the body cells causing release of energy
47
function of insulin:
controls blood sugar levels
48
define homeostasis
the maintenance of a constant internal environment (despite changes in the external environment)
49
define negative feedback:
a change in the internal environment that starts a process that returns the conditions to normal
50
What is thermal regulation?
balancing the heat generated and heat lost from the body
51
What are four ways in which heat can be lost or gained?
radiation, convection, conduction, evaporation
52
what is radiation:
the emission of electromagnetic waves by all objects warmer than absolute zero.
53
what is convection:
transfer of heat by the movement of air or liquid past a surface
54
what is conduction:
direct transfer of thermal radiation between molecules of objects in direct contact with each other
55
what is evaporation:
removal of heat from the surface of a liquid that is losing some molecules as a gas
56
what are three things your body does when you are hot?
vasodilation, sweat, hairs lie flat
57
what are three things your body does when you are cold?
vasoconstriction, hairs on end, shiver
58
What are three ways tho body loses water?
faeces, urination, sweating, breathing
59
name three functions of the kidney:
removal of urea, adjustment of salt levels, adjustment of water content
60
What are two processes that occur in the nephron?
ultrafiltration, reabsorption
61
What is the four step process to ultrafiltration?
- blood from renal artery flows through glomerulus
- a high pressure is built up squeezing water, urea, ions and glucose out of the blood and into the Bowman's capsule
- the membranes between the glomerulus and Bowman's capsule act as filters. Big molecules are NOT squeezed out (blood cells, proteins)
- the filtered liquid is known as the glomerulus filtrate
62
What is the three step process to reabsorption?
- All glucose is reabsorbed in proximal convoluted tubule so it can be used in respiration
- sufficient ions are reabsorbed
- water is reabsorbed in the collecting duct
63
What is osmoregulation?
the balance of water content in the body
64
What does ADH do to the collecting ducts?
makes them more permeable
65
Name the four layers in a leaf from top to bottom:
upper epidermis, palisade, spongey mesophyll, lower epidermis
66
What are four leaf adaptations?
stomata, thin leaf shape (decreased diffusion distance), spongey mesophyll layer is moist and has large SA because of air spaces.
67
How can you test for starch in a variegated plant?
1. place leaf in hot water to melt waxy cuticle
2. transfer leaf to ethanol to remove colour/chlorophyll
3. add to hot water bath
4. rinse and cool leaf
5. place iodine on it, observe colour change
68
name four minerals needed by plants:
phosphate, magnesium, potassium, nitrate
69
What is magnesium needed for in plants?
photosynthesis/chlorophyll
70
What are nitrate ions needed for in plants?
growth and enzymes
71
What is the carpel made of?
stigma and style
72
What is the stamen made of?
filament and anther
73
Define pollination:
transfer of pollen form the anther of one flower to the stigma of another
74
Five differences between insect and wind:
scent, colour, nectary, pollen, anther positioning, sticky vs, feathery stigma
75
What is the colour change of hydrogen carbonate indicator from high conc CO2 to low conc?
yellow - orange - purple
76
What are the six steps to fertilisation?
- pollen tube grows down style due to enzymes secreted by the tip
- male gamete travels down tube to to ovule
- male gamete enters through micropyle
- then fuses with nucleus of female gamete
- zygote is formed
77
What does the ovule turn into after fertilisation?
seed
78
Why is water need for seed germination?
soften testa and activate enzymes to break down food store to release energy.
starch ---amylase--> maltose
maltose---maltase---> glucose
79
What three conditions are needed for germination and why?
warmth: optimum enzyme funciton
water - activate enzymes, soften testa
oxygen - aerobic respiration to release energy for growth and germination
80
What are a plants responses to stimuli called
tropisms
81
how do auxins work?
distributes away from light via diffusion and accumulates in shaded part of stem causing cell elongation on dark side
82
How is bronchitis caused? + effects
Sticky mucus in lungs traps pathogens and is normally swept away by cilia. Hot cigarette smoke and chemicals paralyses the cilia leading to a smokers cough and bronchitis.
83
How is emphysema caused? + effects
smoke damages the walls of the alveoli meaning the air spaces are larger than normal, reducing efficiency of gas exchange. this causes difficulty breathing.
84
What is respiration?
the production of energy/ATP from organic molecules
85
what is the word equation for anaerobic respiration in humans?
glucose --> lactic acid (+energy)
86
what is the word equation for anaerobic respiration in plants?
glucose --> ethanol + carbon dioxide + water
87
What is the function of lymphocytes?
to produce antigens that bind to and neutralise pathogens
88
What is CHD caused by?
deposited fat and cholesterol in coronary arteries
89
What are 4 features of arteries?
small lumen, thick wall, no valves, high BP
90
Do veins have valves?
yes
91
Describe the primary immune response:
1. lymphocytes produce antibodies that aim to be complementary to the antigens on the pathogen
2. some lymphocytes may become memory cells
3. antibodies cause pathogens to stick together, making them easy as a target for destruction by pathogens
92
Describe the secondary immune response:
1. memory cells will have stayed in blood stream and recognised the pathogen quickly
2. therefore antibodies can be produced quicker and in higher quantities
93
What are the 5 stages of circulation?
1. blood enters atria - tri and bicuspid valves are still sealed
2. atria walls contract increasing BP forces valves open and blood into ventricle
3. when ventricles are full they contract, causing high BP, meaning try and bi cuspid valves close
4. ventricles continue to contract pushing valves open and blood into arteries
5. valves close again when BP gets higher in arteries than in ventricles
94
What are the 4 functions of the circulatory system?
provide oxygen to cells for respiration, remove CO2, transport nutrients from gut, transport urea to kidneys
95
define community:
All the organisms present in an ecosystem
96
Define population
All the organisms of one species found in a particular area
97
define ecosystem:
All the organisms living in a particular area and the non-living components that the organisms interact with
98
define habitat:
The place where an organism lives
99
What are the five greenhouse gases?
Carbon dioxide, water vapour, nitrous oxides, methane, CFCs
100
Name four effects of global warming:
sea level rise, extreme weather, species go extinct, coral bleaching
101
What are three effects of deforestation?
trees usually burnt releasing CO2, disruption to carbon cycle, destruction of habitats
102
How do greenhouse gases work?
greenhouse gases absorb more of the solar radiation that is reflected back from the Earth's surface - trapping heat and keeping it in the atmosphere.
103
Describe eutrophication:
1. fertilisers leach the soil into the waterways
2. algae blooms due to accelerated growth by fertilisers
3. no sunlight can reach the aquatic plants, meaning less photosynthesis occurs, and less oxygen is produced
4. plants die and get broken down by decomposers. increased respiration by decomposers reduces oxygen further
5. aquatic life dies
104
How is the information in the nerve cells transmitted?
nerve impulses
105
define a neurone:
a single cell of the nervous system
106
define a nerve:
a group of axons of many neurones
107
Describe the reflex arc:
when stimulus is detected by receptors, nerve impulse is sent along sensory neurone to CNS. In CNS sensory neutron passes message onto relay neurone. Relay neurones relay the impulse to motor neurone. Muscle then contracts.
108
what is the function of the conjunctiva?
lubricates and protects surface of eye
109
what is the cornea?
the tough outer layer of the eye
110
what is the function of the lens?
allows the light to be focused on retina
111
what is the function of the optic nerve?
it carries impulses from the receptor to the brain
112
What happens in the eye when looking at distant objects?
ciliary muscles relax, pulling suspensory ligaments tight, making lens go thin and refract light less
113
What is neurotransmitter?
chemical substance that transfers a message from one neurone to another
114
What are the five steps of an impulse travelling across a synapse?
1. impulse moves down axon towards terminal
2. vesicles containing NT moves towards pre SM
3. NT is released into synapse and diffuses across post SM
4. NT binds onto receptor on the post SM
5. when enough receptors have NT, a new impulse is generated on the post SM.
6. NT can then be broken down by enzymes
115
What are the three steps to oogenesis?
follicle --> ovulation --> corpus luteum
