PAPER 1 GCSE Flashcards
1
Q
Factors affecting the rate of diffusion
A
- Surface Area : Volume- if surface are is large compared to the volume, the rate of diffusion will be faster
- concentration gradient
- distance (travelling a shorter distance)
- temperature (particles move quicker with a higher temperature)
2
Q
What is diffusion
A
Diffusion is when particles spread from an area of high concentration to an area of low concentration. The particles move along a “concentration gradient” and this process uses no energy
3
Q
What is active transport
A
Active transport uses energy to move substances against their concentration gradient.The energy comes from respiration
4
Q
What is osmosis
A
Osmosis is the net movement of water molecules from an area of high water potential to an area of low water potential across a permeable membrane
5
Q
Diffusion in non living organism experiment
A
- Place a few potassium permanganate crystals in a beaker of water.
- Note the colour of the water after a period of time eg. 15 minutes.
- Note the colour of the water after a longer period of time eg. 1 hour.
6
Q
Osmosis in a non living organism experiment
A
- Tie one end of a visking tube with a piece of string.
- Pour some solution into the visking tube.
- Insert a capillary tube into one end of the visking tubing.
- Use a marker to mark the initial water level in the visking tubing.
- Immerse the visking tubing in a beaker of distilled water.
- Note the difference in water level in the capillary.
7
Q
Osmosis in living organism experiment
A
- Accurately measure and record the mass of each potato cylinder.
- Measure sugar solution and put into boiling tube
- Repeat for other concentrations of the solution and distilled water into boiling tubes
- Add one potato cylinder (of known mass) to each boiling tube.
- Leave the cylinders in the boiling tubes for at least 15 minutes in a test tube rack.
- Measure the mass of each cylinder and record your measurements in the table. Calculate
the percentage changes for each cylinder.
8
Q
What is the trachea
A
Tube lined with rings of cartilage
Goes from the mouth to the lungs where it splits
The cartilage prevents the trachea from collapsing
9
Q
What are the ribs
A
Bones that protect the lungs from damage - the ribcage can expand or contravt eith breathing
10
Q
What are the bronchi
A
The two tubes that the trachea split into
They have cadtilage rings to lrevent them from collapsing
11
Q
What are the bronchioles
A
The small tubes that come from the bronchi that have alveoli on the end
12
Q
What are alveoli
A
Small air sacs at the end of the bronchioles
13
Q
What are the pleural membranes
A
Very slippery to help reduce the friction of the lungs rubbing along the inside of the ribcage
14
Q
Action of intercostal muscles when humans inhale
A
External intercostal muscles contract and make the ribcage lift upwards and outwards
15
Q
Actions of intercostal muscles when humans exhale
A
External intercostal muscles relax
Internal intercostal muscles can be contracted consciously to expel air faster
16
Q
Action of diaphragm when inhaling
A
Diaphragm contracts
It flattens out and moves downwards
This increase the volume of the thorax (chest cavity)
The air pressure decreases inside the thorax
The air pressure outside the lungs is higher and moves into the lungs
17
Q
Action of diaphragm when exhaling
A
Diaphragm relaxes
Forms a dome shape and moves upwards
This decreases the volum eof the chest cavity (thorax)
Air pressure increases inside the thorax
Air pressure inside the lungs is higher and so moves out of the lungs
18
Q
How are alveoli adapted for gas exchange by diffusion
A
- alveoli are small and have a large surface area to volume ratio
- walls of alveoli are one cell thick to allow for faster diffusion
- capillaries are very close to the alveoli fo allow a short diffusion pathway
- inside of alveoli is lined with a surfactant that sfops ghd alveoli from collapsing and also allows oxygen and co2 to diffuse through
19
Q
How can smoking cause coronary heaft disease
A
- nicotine causes the blood pressure to increase
- this can damage the lining of the arteries
- the damaged arteries can start to have fatty deposits build up in the damaged areas
- these can block the arteries leading to the heart causing less oxygen to reach the heart cells so they cannot respire and die
20
Q
Experiment to show the effect of exercise on breathing
A
Measure the number of breaths per minute at rest
Exercise for a set amount of time
Measure fhe breathing rate directly after the exercise
Measure breathing rate every minute after exercise until if reaches back to normal breathing rate
21
Q
How do unicellular organisms move substances in and out of the cell
A
Diffusion
Unicellular organisms have large surface area to colume ratio
Substances (nutrition and oxygen) can more easily diffuse into or out of the centre of the cell
22
Q
Why do multicellular organisms rely on transport systems
A
Large multicellular organisms have smaller surface area to volume ratios than unicellular organisms
Cells deep inside the organism camnot recieve nutrients and oxygen fast enough to survive without a transport system
A transport system allows nutrients and pxygen to reach every cell and also allows waste to not build up and become toxic
23
Q
What is transported in the phloem
A
Sucrose and amino acids between the leaves and other parts of the plant
24
Q
What is transported in the xylem
A
Water, nitrates and magnesium ions from the roots to other parts of the plant
25
What does the plasma transport
Carbon dioxide, digested food, urea, hormones and heat energy
26
How are red blood cells adapted to their function
- biconcave shape to increase surface area to volume ratio to help oxygen diffuse more quickly
- no nucleus to make more space for haemoglobin to carry more oxygen
- haemoglobin is present to carry oxygen
27
How do phagocytes respond to disease
Phagocytes - ingest / engulf pathogens and use digestive enzymes to kill them
28
How do lymphocytes respond to disease
Produce antibodies that bind to a specific pathogens antigens
These can kill pathogens or cause pathogens to clump together so that they can more easily be engulfed by phagocytes
29
Through which blood vessels does oxygenated blood flow
Aorta, pulmonary vein, coronary arteries
30
Through which blood vessels does deoxygenated blood flow though
Vena cava, pulmonary artery
31
What do the coronary arteries do
Provide oxygenated blood and nutrients to the cardiac muscles
32
Why is the left ventricle wall thicker that the right
So that it produces a higher blood pressure so it can pump blood further around the body
33
What is the role of the valves
Prevents back flow of blood so it can flow in one direction
34
Advantages of a double circulatory system
Under higher pressure so can supply oxygenated blood further and helps organism with higher metabolisms and higher rates of respiration by supplying more oxygen faster
35
Why does heart change increase during exercise
Muscles contract more meaning that more respiration occurs
| More oxygen is needed so the heart rate increases to supply the extra oxygen to the muscles
36
How is an artery adapted for its function
Thick elastic and muscular walls to withstand high blood pressure
Lumen is smaller to maintain high blood pressure
37
Artery function
To transport oxygenated blood around the body
38
How is the vein adapted for its function
Has thinner walls as there is a lower blood pressure
| The lumen is larger and veins have valves
39
Role of veins
To transport deoxygenated blood back to the heart
40
How is a capillary adapted for its function
Lumen is only one red blood cell thick
| Walls are one cell thick to allow a short diffusion distance
41
Capillaries role
To allow the exchange of gases in the lungs and in the body
42
What is homeostasis
The maintenance of a constant internal environment
43
What is a stimulus
A change in the surroundings of an organism that produces a response
44
What is a receptor
A cell or organ that detects a stimulus
45
What is an effector
An organ that brings about a response (a muscle or gland)
46
What are geotropic responses
Roots grow towards the pull of gravity
| Shoots grow away from the pull of gravity
47
How does auxin control the way the plant responds to light
The tip of the shoot produces a chemical auxin
Auxin causes cells to elongate
Light causes auxin to move to the darker less lit side of the shoot
This the plant to bend towards the light source
48
What is nervous communication
When neurones send electrical impulse to each other as well as parts of the body
49
What is hormonal communication
When glands produce a hormone and that is transported around the body via the blood
The hormone interacts with its specific receptor
50
What does the central nervous system consist of
Brain and spinal cord
51
What are synapses
Synapses are the small gaps between neurones
52
how an electrical impulse is converted to a chemical impulse back to an electrical impulse at a synapse using neurotransmitters
The electrical impulse reaches the bulb, causing it to release neurotransmitters into the synapse
The neurotransmitters diffuse across the synapse and then bind to the receptors on the membrane of a bulb, which causes a electrical impulse to be created in the neurone
The electrical impulse now travels along the poor synaptic membrane
53
What is the reflex arc
The receptor detects the stimulus
Impulse travels from receptor to the sensory neurone
Then impulse travels to the relay impulse
Relay neurone transfers impulse to a motor neurone
Impulse travels along the axon of the motor neurone to a muscle in the arm (effector) which contracts and moves hand away from heat
54
What is the retina
Contains rod and cone cells that detect light and convert light energy into electrical impulses that travel to the brain via the optic. Ed e
Cone cells = colours (wavelengths)
Rod cells = presence of light (low light conditions)
55
Optic nerve
Takes impulses from the eye to the brain
56
Lens
Helps focus light onto the retina
57
Ciliary muscles and suspension ligaments
These help change the shape of the lens so that it can focus on close and far objects
58
The pupil is
The hole that light comes through
59
The iris
Controls the amount of light going into the eye
| If there is a lot of light it makes the pupil smaller as a lot of light can damage the retina
60
The cornea
Helps focus the light through the lens
61
Conjunctiva
Helps protect the eye from damage
62
Choroid
Is black to stop light reflecting around the inside of the eye (also has blood vessels in it to supply cells with oxygen)
63
Fovea
Area where there is a high concentration of cone cells
64
Why does the eye respond to different light intensities
In high levels of light intensity the retina can be damaged
So the amount of light entering the eye needs to be controls
In bright light circular muscle contract and radial muscles relax so the pupil constricts
In dim light the circular muscles relax and the radial muscles contract so the pupil dilates
65
When the eye focuses on a far object
The lens become less rounded and more flat because the ciliary muscles relax which make the suspension ligaments tighter
66
When the eye focuses on a near object
The lens becomes more rounded and convex
| The ciliary muscles contract which makes the suspension ligaments slack
67
Vasodilation
As internal body temp increases the arteriole closer to the skin open wider
More heat can be lost by radiation to the surroundings
68
Vasoconstriction
As the internal body temp decreases the arteriole close to the skin become smaller
Less blood goes to the skin therefore less heat is lost to the surroundings
69
How does sweating help regulate body temperature
As the body temperature increases the skin starts to release sweat, the extra body heat transfers energy to the sweat causing it to evaporate
This transfers the heat energy to the surroundings
70
Role and effects of adrenaline
Increases heart rate and breathing rate to prepare the body for physical activity
(Adrenal glands on top of the kidneys)
71
Roles and effects of insulin
Controls the levels of glucose in the blood
Lowers glucose concentration in the blood by causing cells to take in glucose
(Pancreas)
72
Roles and effects of testosterone
Controls puberty in boys
Helps the male secondary sexual characteristics develop
(Testes)
73
Roles and effects of progesterone
Controls the thickness of the lining of the uterus and regulates the menstrual cycle
High levels of progesterone keeps the lining of the uterus thick
(Ovaries and placenta)
74
Role and effects of oestrogen
Controls puberty in girls
Helps the female secondary sexual characteristics develop
(Ovaries)
75
What does fertilisation include
The fusion of a female and male gamete to produce a zygote that undergoes cell division and develops into an embryo
76
What does petal do
Is brightly coloured to attract pollinating animals ie. Insects
77
What does anther do
Produces pollen and rubs it onto the pollinating insect
78
What does the filament do
Holds the anther up and controls its height
79
What does the stigma do
Receives the pollen
80
What does the ovary do
This contains the ovules and ova (egg cells). The ovary turns into the fruit after fertilisation occurs
81
What do ovules do
These contain the egg cells and turn into the seeds after fertilisation occurs
82
Adaptations of insect pollinated
Large and brightly coloured petals
Anthers and stigma inside flower so insects must make contact
Sticky stigma to attach pollen from insects
Pollen grains are sticky, larger or have hooks
83
Adaptations of wind pollinated
Small dull petals
Anthers and stigma outside flower so they are exposed to the wind
Smooth and smaller inflated pollen grains to carry in the wind
Feather stigma to increase SA to catch pollen grains in wind
84
Conditions needed for a seed to germinate
Warm temperatures so enzymes can act efficiently
Water to help swell up the seed so chemical reactions can take place in solution
Oxygen is needed for respiration
85
Germinating seeds utilise food resources until
The seedling can carry out photosynthesis
86
Runners (asexual reproduction in plants)
Runners in plants (eg. Strawberry plants grow from the stem)
From the runners, new plants can grow
The new plants are genetically identical to the parent plant
87
Cuttings (artificial asexual reproduction in plants)
A piece of a plants stem is cut off
The cut piece is placed into damp soil/compost(
Cutting develops into a new plant
88
What role does oestrogen have in the menstrual cycle
Helps the body repair the lining of the uterus
As the level of oestrogen increases it inhibits the production of FSH
High levels of oestrogen promotes the secretion of LH
89
What role does progesterone have in the menstrual cycle
Progesterone maintains and thickens the uterus lining
| Also inhibits the production of FSH and LH so no eggs mature
90
What does the placenta do
The placenta develops from foetal tissues and allows the exchange of materials between mother and foetus. It has a large number of blood vessels that do not touch. This ensures there is no mixing of the maternal and foetal blood.
91
Which substances diffuse from the mother’s blood into the foetus?
Oxygen - respiration
Glucose - respiration
Amino acids - proteins
Antibodies - passive immunity
92
What is the role of the amniotic fluid?
To protect the baby from bumps
If it wasnt there, the baby would move around the womb too much, causing damage to both the baby and the womb
Also doesnt expose the baby to any extreme temperature
93
The genome is
The entire DNA of an organism
94
A gene is
A section of a molecule of DNA that codes for a specific protein
95
A nucleus of a cells contains
chromosomes on which genes are locates
96
genes exist in alternative forms called
alleles which give rise to differences in inherited characteristics
97
define dominant
allele that will be expressed in the phenotype
98
define recessive
allele will not be expressed in the phenotype if there is dominant type of that allele present
99
define homozygous
genotype with both alleles being the same
100
define heterozygous
genotype where each of the two alleles are different
101
define phenotype
how the gene is expressed in the organism (appearance)
102
define genotype
the alleles that the organism has for a certain characteristic
103
division of a diploid cell by mitosis produces
two cells that contain identical sets of chromosomes
104
mitosis occurs during
growth, repair, cloning and asexual reproduction
105
division of a cell by meiosis produces
four cells, each with the half the number of chromosomes, and that this results in the formation of genetically different haploid gametes
106
random fertilisation produces
genetic variation of offspring
107
in human cells the diploid number of chromosomes is
46
108
in human cells the haploid number of chromosomes is
23
109
mutation is
a rare, random change in genetic material that can be inherited
110
How Darwin’s theory of evolution by natural selection occurs
- there is a variation within a species
- the variation is caused by mutations
- changing conditions in an environment favours one particular form of the species (which have a selective advantage)
- more of the individuals with the selective advantage survive and the rest die
- the mutations that has given the selective advantage to the individuals is more likely to be passed on as offspring (as more individuals with the advantage survive long enough to reproduce)
111
resistance to antibiotics will increase in
bacterial populations
112
an increase in resistance to antibiotics can lead to
infections being difficult to control
113
selective breeding will develop -
plants and animals with desired characteristics
