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GCSE - Biology > Biology Higher 3 GCSE > Flashcards

Biology Higher 3 GCSE Flashcards

1
Q

What are the 2 main types of cells

A

Eukaryotic- Have a nucleus and are relatively large, between 10µm and 100µm
Prokaryotic cells- Don’t contain a nucleus. Usually bacterial cells. Their genetic material floats around in the cytoplasm. Usually between 1µm to 10µm.

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2
Q

µm to mm

A

divide by 1000

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3
Q

Examples of prokaryotic cells

A

E.coli- causes an upset stomach

Streptococcus- causes a cough

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4
Q

What happens in the nucleus

A

Controls the activities of the cell and holds the genetic material. Also contains the instructions needed to make new cells or organisms

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5
Q

What happens in the mitochondria

A

Where respiration happens. Glucose and oxygen react to make energy

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6
Q

What happens in the cell membrane

A

A selective barrier that controls what enters and leaves the cell. Also contains receptor molecules

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7
Q

What happens in the Cytoplasm

A

A ‘jelly-like’ substance where the chemical reactions to keep the cell alive happen.

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8
Q

What are extra subcellular structures the plants need

A

Vacuole- cell sap, that helps to keep the cell rigid and firm
Cell wall- Surrounds the cell and is made of cellulose fibre, keeping it rigid.
Chloroplast- Contains Chlorophyll, which transfers energy from the Sun to the plant, used in photosynthesis.

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9
Q

Subcellular structures that prokaryotic may have

A

Flagella: allows the cell to swim through liquids
Pili: hair-like structures that allows the cell to attach to structures like your digestive track.
Slime capsule: Outside the cell wall and protects the cell from drying out, and stick to smooth surfaces.
Plasmid: Used to store extra genes May be used in times of stress.

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10
Q

Why do we have to stain cells

A

Most cells are actually colourless so stains are used to make them easier to observe and to see.

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11
Q

How can you use a stain

A

Put the cell on a glass slide
Add 1 drop of stain
Put a plastic coverslip on top
Tap the coverslip gently to get rid of any air bubbles

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12
Q

Stains

A

Methylene blue - nucleus of animal cells
Iodine - nucleus of plant cells
Crystal violet- bacterial cell walls

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13
Q

what is an electron microscope

A

they use electrons instead of light to produce an image

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14
Q

2 types of electron microscopes

A

Transmission Electron Microscope- a beam of electrons passes through a very thin slice of the sample
Scanning Electron Microscope- Produces a 3D image by sending a beam of electrons across the surface of the specimen, so the reflected electrons can be used to produce an image

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15
Q

Pros and cons of an electron microscope

A 
Expensive 
Difficult to move 
Sample preparation is complex 
Specimens must be dead
Black and white images are produced, but false colour can be added 
High resolution
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16
Q

Pros and cons of a light microscope

A 
Cheap 
Small and portable 
Simple to prepare a sample
Natural colour of stain is seen
Specimen can be living or dead.
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17
Q

What is in a DNA nucleotide

A

Phosphate
Deoxyribose
Base

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18
Q

How many chromosomes do you have

A

46

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19
Q

What is a gene

A

A shorter section of a DNA

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20
Q

Transcription

A
  1. DNA unzips
  2. mRNA comes in
  3. One of the strands acts as a template as the complementary bases are attached
    (U instead of T)
  4. mRNA comes off
  5. DNA zips
    mRNA moves to the ribosomes in the cytoplasm
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21
Q

Translation

A

3 Bases join together to make an amino acid. These join together to make long chain, a protein. The ribosomes read the mRNA in groups of three, called codons.

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22
Q

What is the active site

A

On the enzyme, the space where the substrate fits

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23
Q

what factors affect enzyme controlled reactions

A

temperature
(denatured)
pH
Substrate concentration

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24
Q

What is a metabollic rate

A

The speed at which your cells can transfer energy from its food to chemical stores.

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25
Q

What does lipase break down

A

Lipids- 3 fatty acids and 1 glycerol molecule

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26
Q

Where is there a lot of mitochondria

A

muscle cells

because they are contracting and need energy

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27
Q

Anaerobic respiration in humans

A

When there is a lack of oxygen and the glucose isn’t broken down properly
It produces lactic acid instead

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28
Q

Anaerobic respiration in plants

A

fermentation

C6H12O6 -> 2C2H5OH + 2C02

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29
Q

Stages in photosynthesis

A

Stage 1: Light dependant- light is used to split water into hydrogen and oxygen.
Stage 2: Light independent- carbon dioxide combines with hydrogen to make glucose

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30
Q

what happens to the glucose produced

A 
cellulose- cell walls
proteins- growth and repair 
fats and oils- food store and growth 
sucrose- stored in fruit
starch- food store
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31
Q

factors affecting photosynthesis

A

light intensity
carbon dioxide
temperature

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32
Q

rate of photosynthesis

A

rate = 1/ timw

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33
Q

relative light intensity

A

rli= 1/ distance from light source2 (squared)

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34
Q

how can you change the co2 concentration

A

add different masses of potassium hydrogen carbonate powder to the water

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35
Q

how can you change temperature

A

water bath

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36
Q

diffusion

A

movement of particles from an area of HIGH CONCENTRATION to an area of LOW CONCENTRATION

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37
Q

Factors affecting diffusion

A

decrease the distance
increase surface area
increase concentration gradient

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38
Q

Osmosis

A

diffusion of water across a selectively permeable membrane from an area of HIGH WATER POTENTIAL to an area of LOW WATER POTENTIAL

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39
Q

Active transport

A

Uses energy and carrier proteins to transport molecules from an area of low concentration to an area of higher concentration

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40
Q

Examples of active transport

A

Glucose transported into the bloodstream

In nerve cells- pumps out sodium and potassium back in

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41
Q

Mitosis

A

IPMATC

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42
Q

Why do we need mitosis

A

It helps to repair damaged tissues, and replace worn out cells.
2 identical daughter cells are made

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43
Q

How is a sperm cell specialised

A

It has a
flagella
lots of mitochondria
acrosome

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44
Q

where are stem cells found in plants?

A

a plant doesn’t stop growing, but only the meristems grow, because they can differentiate
they have very thing walls, small vacuoles and no chloroplasts compared to other plant cells

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45
Q

when do the guard cells open?

A

when there is enough light and water. They swell up and become turgid

46
Q

Why do plants wilt

A

If a plant loses more water than it can take in.

47
Q

what causes short-sightedness

A

eyeball is too long or the lens is too strong

needs a concave lens to be fixed

48
Q

what causes long-sightedness

A

eyeball is too short or the lens is too weak

needs a convex lens to fix it

49
Q

What does the suspensory ligament do

A

It connects the ciliary muscle to the lens

50
Q

when does the lens become convex

A

ciliary muscle contracts and the lens becomes fatter

51
Q

when does the lens become concave

A

ciliary muscle relaxes and the lens becomes thinner

52
Q

what do rods and cones do

A

rods- respond to light in dark

cones- respond to different colours

53
Q

what does the cerebrum do

A

learning, memory and personality

54
Q

what does the hypothalamus do

A

water balance and temperature

55
Q

what does the pituitary gland do

A

releases hormones

56
Q

what do the cerebellum do

A

posture and balance

57
Q

what does the medulla do

A

involuntary actions such as breathing rate and heart rate

58
Q

how can you investigate brain function

A

Computer Tomography-
Use X-Rays to create 3D images of anywhere in the body, and the position of any abnormalities

MRI- Magnetic Resonance Imaging
Powerful magnets to identify brain abnormalities. (fMRI does the same in real time) They show areas of the brain with increased blood flow.

59
Q

Ethical problems with investigating brain function

A

patients must give consent for their information to be given
Many case studies need to be analysed to draw a conclusion
Several areas of the brain may be used at one point
Animal testing is bad

60
Q

FSH

A

Follicle Stimulating Hormone
Secreted by the pituitary glands
travels to the ovaries where is causes the egg to mature
Also stimulates the ovaries to produce oestrogen

61
Q

LH

A

Luteinising Hormone

When levels of this reach a peak, ovulation is triggered

62
Q

Oestrogen

A

Causes the lining to be built up
Made by the ovaries
As this rises, it inhibits the production of FSH, preventing more than 1 egg maturing

63
Q

Progesterone

A

Maintains the uterus lining

Inhibits LH

64
Q

Types of contraception

A

Non-hormonal: Barrier methods that prevents physical contact
Hormonal: It uses hormones to disrupt the female reproductive system

65
Q

Non-hormonal contraception:

A

Condom
Intrauterine device
Cervical cap

66
Q

Condom

A

Placed over the penis to prevent the sperm entering the vagina
Prevents STDs

67
Q

Cervical cap

A

Inserted into the vagina to cover the cervix. Removed 6 or more hours after the sexual intercourse
Must be used with spermicide

68
Q

Intrauterine Device

A

Inserted into the uterus and releases copper to kill the sperm. Remains effective for 5 to 10 years

69
Q

Hormonal Contraception

A

Combined pill
Progesterone pill
Intrauterine System

70
Q

Combined pill

A

Prevents ovulation by thickening the mucus, stopping the implantation into the uterus lining
Must be used 21 days of the menstrual cycle

71
Q

Progesterone pill

A

Thickens mucus and thins the lining of the uterus so there physically can’t be a implantation.
Must be taken at around the same time daily

72
Q

Intrauterine System

A

Thickens mucus and thins the lining of the uterus so there physically can’t be a implantation.
Effective for 3-5 years

73
Q

Causes of infertility

A

blocked sperm ducts
not enough sperm
lack of mature eggs
failure to release an egg

74
Q

Fertility treatment- using hormones

A

FSH- can be given to stimulate her eggs to mature.(triggering oestrogen production)

75
Q

IVF

A

Collecting eggs and sperm, then mixing them outside of the body. then implanting it back into the mother

76
Q

Considerations with ivf

A 
Multiple pregnancies
failure 
Not natural 
Allows people to have children 
Expensive
Allows women to focus on their careers and have children later
77
Q

Phototropism

Gravitopism

A

Growing towards the light

Growing in the same direction as gravity

78
Q

Uses of ethene

A

Ripening fruit by stimulating the conversion of starch into sugars.

79
Q

Uses of gibberellins

A

Promotes growth. Uses to control dormancy

80
Q

Uses of auxins

A

Killing weeds (uncontrolled growth)
Promoting root growth (used for cloning and they will dip the stem into it)
Delaying ripening
Produce seedless fruits (Apply auxins to unpollinated flowers)

81
Q

Type 1 Diabetes

A

Cannot produce insulin
Immune system kills cells
Begins at childhood

82
Q

Type 2 Diabetes

A

Cannot use the insulin

Linked to obesity

83
Q

Where does ultra-filtration happen

A

Bowman’s capsule

84
Q

Where does selective reabsorption happen

A

in the area after the bowman’s capsule

85
Q

where does salt and water regulation happen

A

loop of henle and the collecting duct

86
Q

Where does protein go

A

It’s too large to fit in the capsule so it stays in the bloodstream

87
Q

What happens in the selective reabsorption

A

glucose is all reabsorbed

sometimes some salt and water is reabsorbed too

88
Q

what happens in the salt and water regulation part

A

according to the amount of ADH etc, salt and water may be taken away

89
Q

isotonic

A

contains the same amount of ion concentrations as the blood

90
Q

hypertonic

A

more glucose and salts

91
Q

hypotonic

A

less glucose and salts

92
Q

CNS

A

Consists of the brain and the spinal cord

93
Q

PNS

A

Consists of all the neurones that connect the CNS to the rest of the body.

94
Q

Damage to your CNS or PNS could occur from

A

Injury
Disease
Genetic condition (Huntington’s disease)
Ingesting a toxic substance such as lead

95
Q

Damage to PNS can cause:

A

Inability to detect pain
Numbness
Loss of coordination

96
Q

Damage to the CNS can cause:

A

Loss of control of body systems
Paralysis
Memory loss or processing difficulties

97
Q

Can the CNS or PNS regenerate?

A

The PNS can regenerate and minor nerve damage often self heals.
However, CNS can’t regenerate.

98
Q

Treatments for the brain

A

Radiotherapy (brain tumours)
Chemotherapy (brain tumours)
Surgery to remove damaged brain tissue
Deep brain stimulation- inserting an electrode to stimulate brain function

99
Q

Why is the CNS so hard to repair?

A

The spinal cord consists of 31 pairs of nerves and each has many nerve fibres. Each spinal cord is about 1.5 cm in diameter so it is quite hard to identify and repair something without damaging something else.

100
Q

higher temperatures in enzymes means what

A

they can reproduce faster
they are closer to their optimum temperature
they can respire faster
there are more successful collisions because there is more energy for the particles to move faster into each other, meaning the rate of the reaction increases
HOWEVER
Enzymes may unravel and denature
This is when the active site changes shape and the enzyme is no longer specific, so it means that the substrate can’t fit in the active site anymore, so the rate will decrease.

101
Q

What are embryonic cells used for

A

Development and growth

102
Q

What are adult stem cells used for

A

Repair and replacement

103
Q

What is differentiation

A

When cells become specialised at one job.

104
Q

How can shoot tips of a plant regenerate into a whole plant

A

The shoot tips of a plant are made up of meristem tissues. They produce unspecialised cells that can be divide and form any type of cell, being able to regenerate an entire plant.

105
Q

Outline how multicellular organisms and single called organisms exchange substance and explain why they exchange substances differently

A

Single called organisms can rely on diffusion alone to exchange substances because they are so small.
It is fairly quick because the distance to travel is quite small, and they have a larger surface area to volume ratio.
In multicellular organisms, diffusion would take too much time due to the low SA:V ratio. Therefore, they use their own specialised exchange organs to exchange substances, they have their own transport systems.

106
Q

Functions of air spaces in leaves

A

Gases can move easier between the cells and they increase surface area to volume ratio for gas exchange.

107
Q

How is water taken up by root hair cells

A

The water travels up by osmosis. There is a high concentration of water in the soil compared to the roots. The water travels cell by cell until it reaches the xylem.

108
Q

How is the small intestine changed to carry out it’s function

A

It has vili, which increases it sa:v ratio for absorption, allowing it to happen quickly. The small intestine has a good blood supply. The vili have 1 single layer for surface cells, meaning the gases don’t need to travel a large distance to be absorbed.

109
Q

Why is the human circulatory system described as a double circulatory system

A

It consists of 2 circuits joined together, the first circuit pumps deoxygenated blood to the lungs and returns with oxygenated blood. The second pumps oxygenated blood to the body and return with deoxygenated blood.

It goes around twice in the heart in one cycle.

110
Q

Why is a double circulatory system good

A

It can be pumped out of the heart at higher pressures, increasing blood flow to the tissues, meaning more oxygen can be transported.

111
Q

What is in blood

A

Plasma (water, hormones and antibodies, amino acids, glucose etc. )
Red blood cells - carry oxygen
White blood cells- have antibodies
Platelets- allows the blood to clot.

112
Q

Xylem walls

A

They are thick, made form lignin and they give the plant support.

GCSE - Biology (28 decks)

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