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CCEA GCSE (S1) > S1 Biology > Flashcards

S1 Biology Flashcards

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1
Q

What is a microscope?

A

An instrument that makes small objects look larger

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2
Q

What is resolution?

A

The ability to clearly distinguish two objects very close together as being separate

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3
Q

How do you calculate magnification (M)?

A

Length of image (I) / Actual length (A)

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4
Q

What is I ( Length of image )?

A

The size of a magnified object

 I= M x A
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5
Q

What is A ( Actual Length )?

A

The actual length of an object ( before magnification )

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6
Q

What does an animal cell contain?

A

Nucleus, Cytoplasm, Cell membrane, Mitochondria

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7
Q

What does a plant cell contain?

A

Nucleus, Cytoplasm, Cell membrane, Mitochondria, Cellulose cell wall, Vacuole, Chloroplasts

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8
Q

What does a bacterial cell contain?

A
  • Non-cellulose cell wall (peptitoglycan),
  • Plasmids,
  • Cytoplasm,
  • Circular chromosome,
  • Cell membrane
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9
Q

What is the function of the cell membrane?

A

To allow the exchange of substances in and out of cells
(Through it’s selective permeability)

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10
Q

What is the function of the cytoplasm?

A

Main part of the cell were all chemical reactions take place. Granular material

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11
Q

What is the function of the nucleus?

A

Contains chromosomes which carry genes

Also

Controls the functions of a cell

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12
Q

What is the function of the mitochondria?

A

Cellular respiration

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13
Q

What is the function of the cell wall?

A

To protect and to provide support for the structure

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14
Q

What is the function of the vacuole?

A

Contains cell sap that, when full, pushes the cell membrane into the cell wall making the cell more rigid, providing more support

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15
Q

What is the function of the chloroplasts?

A

Contains chlorophyll which traps light, helping the plant to photosynthesise

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16
Q

What are stem cells?

A

Cells that retain their ability to divide and differentiate into a wide variety of specialised cell types

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17
Q

Where are stem cells found in animals?

A

In the umbilical cord or bone marrow

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18
Q

Where are stem cells found in plants?

A

Meristems at the tip of the roots or shoots

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19
Q

What are embryonic stem cells?

A

Stem cells that can differentiate into any kind of cell

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20
Q

What are adult stem cells?

A

Cells that can only differentiate into a general cell type

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21
Q

What are multicelled organisms?

A

Cells that can form specialised tissues, organs and organ systems

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22
Q

What are the benefits of stem cell transplants?

A

It can treat diseases such as leukaemia and replace damaged body parts

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23
Q

What are the risks of stem cell transplants? (4)

A
  • Pre treatment can kill healthy cells as well,
  • it can transfer viruses and diseases,
  • and can sometimes lead to a formation of a tumour
  • also the body can reject stem cells
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24
Q

What is diffusion?

A

The random movement of molecules from a region of high concentration to a region of low concentration

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25
Q

What factors can affect the rate of diffusion? (3)

A

Temperature - The higher the temperature, the faster the rate of diffusion
Surface Area - The greater the surface area, the faster the rate of diffusion
Concentration Gradient - The greater the concentration gradient (difference) the greater the rate of diffusion

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26
Q

How many micrometres (μm) are in 1 millimetre (mm)

A

1000

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27
Q

How many millimetres (mm) are in 1 metre (m)

A

10000

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28
Q

What is 1 micrometre (μm)

A

10-3 mm -or- 10-6 m

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29
Q

Where does photosynthesis take place?

A

Chlorophyll in chloroplasts

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30
Q

What type of reaction is photosynthesis?

A

Endothermic

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31
Q

What is the word equation for photosynthesis?

A

Carbon dioxide + water -> glucose + oxygen

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32
Q

What is the balanced symbol equation for photosynthesis?

A

6CO2 + 6H20 –> C6H12O6 + 6O2

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33
Q

What is glucose used for in plants? (3)

A
  • Respiration,
  • Stored as starch,
  • Converted to cellulose to make cell walls
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34
Q

How do you destarch a plant?

A

Keep the plant in a dark room for 24 - 48 hours

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35
Q

Explain how to conduct the starch test. (6)

A
  • First, destarch the plant.
  • Then keep the plant in bright light to photosynthesise.
  • Take a leaf and place it in boiling water for 30 seconds to kill the leaf, stopping any chemical reactions.
  • Then place the leaf in boiling ethanol to remove chlorophyll making the leaf brittle.
  • Next, dip it back in the water to soften it.
  • Finally, add iodine on to the leaf. If starch is present, the iodine will turn from yellow-brown to blue-black
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36
Q

What is a variegated leaf?

A

A leaf that only part of contains chlorophyll

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37
Q

How do you investigate the need for carbon dioxide? (5)

A
  • A leaf from a destarched plant can be put into a conical flask with sodium hydroxide solution in it, to absorb all carbon dioxide.
  • Put a cotton ball soaked in sodium hydroxide over the flask to stop any carbon dioxide getting in.
  • Leave the leaf in bright light to photosynthesise.
  • If no starch is present, then carbon dioxide is necessary for photosynthesis.
  • For a control flask, do the same but with water in place of sodium hydroxide solution
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38
Q

How can you measure the rate of photosynthesis?

A
  • By placing pondweed in an inverted funnel filled with water, with a bright light shining over it.
  • Put an upside-down test tube over this and leave it for a certain period of time.
  • Measure the volume of each bubble produced, and divide it by the time taken to get the rate of photosynthesis
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39
Q

What 3 factors affect the rate of photosynthesis?

A
  • Light intensity,
  • carbon dioxide concentration and
  • temperature
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40
Q

What is a limiting factor? (2)

A
  • An environmental factor that limits the rate of reactions
  • due to that factor being present in too small an amount
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41
Q

What is the optimum?

A

The point at which the highest rate of a reaction is achieved

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42
Q

What is the structure of a leaf? (5)

A
  • Waxy cuticle
  • Upper epidermis
  • Palisade mesophyll layer
  • Spongy mesophyll layer
  • Lower epidermis
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43
Q

What are the properties of the waxy cuticle?

A

Thin, Transparent to let light through, Prevents water-loss (waterproof)

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44
Q

How is the cross section of a leaf adapted for light absorption? (3)

A
  • Large surface area of the thin transparent cuticle,
  • presence of many tightly packed palisade mesophyll cells that are rich in chlorophyll and are arranged perpendicularly,
  • thin so short distance for both gases & light to get to every cell
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45
Q

How is the cross section of a leaf adapted for gas exchange? (3)

A
  • Spongy mesophyll cells have a large surface area for gas exchange,
  • Intercellular spaces in the spongy mesophyll layer allow carbon dioxide and oxygen easier entry and exit,
  • Stomata that allow carbon dioxide to enter the leaf and oxygen to exit the leaf
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46
Q

What are the properties of the upper epidermis?

A

No chloroplasts, quite transparent to allow light to pass through

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47
Q

What are the properties of the palisade mesophyll layer?

A

Packed with many chloroplasts, cells arranged vertically so more can fit in

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48
Q

What are the properties of the spongy mesophyll layer?

A

Contains intercellular air spaces, fewer chloroplasts than palisade mespphyll cells

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49
Q

What is the function of the stoma?

A

To allow gases to enter and exit

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50
Q

What is the function of guard cells?

A

To open and close the stomata at night

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51
Q

What is the compensation point?

A

The light intensity at which the rate of photosynthesis is equal to the rate of respiration

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52
Q

What solution is used in the experiment to calculate the compensation point of photosynthesis and respiration?

A

Hydrogen carbonate solution

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53
Q

What is the experiment to find the compensation point of photosynthesis and respiration? (8)

A
  • Set up three test tubes containing water and red hydrogen carbonate solution.
  • In the first one, place normal pondweed.
  • In the second, place pondweed covered in lightproof foil,
  • In the third, place partially shaded pondweed.
  • Set up a bright light beside the test tubes and leave them for a period of time.
  • In the first test tube, the hydrogen carbonate should turn from red to purple as the rate of photosynthesis is higher than respiration. (Less CO2)
  • In the second it should turn from red to yellow as the rate of respiration is higher than photosynthesis. (More CO2)
  • In the last, it should stay red as the rate of photosynthesis is equal to respiration (equal CO2)
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54
Q

What are biological molecules?

A

Molecules made and used by living organisms. Carbohydrates, proteins and fats

Only contain carbon, hydrogen and oxygen (+ nitrogen in the case of proteins)

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55
Q

What are the 7 nutrient groups?

A

Carbohydrates (both starch and small sugars), proteins, fats (or lipids), vitamins, minerals, water, fibre

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56
Q

What is a balanced diet?

A

A diet that includes all of the 7 nutrient groups in the right proportions

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57
Q

What are carbohydrates?

A

Sugars and starch such as glucose and lactose

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58
Q

What do we store carbohydrates as?

A

Glycogen

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59
Q

How many amino acids are there?

A

20

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60
Q

What do we use fats for?

A

Storing energy and providing insulation

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61
Q

What do we use carbohydrates for?

A

Energy

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62
Q

What do we use proteins for?

A

Growth and repair

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63
Q

What are proteins made up of?

A

Long chains of amino acids

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64
Q

What are carbohydrates broken down into?

A

Glucose

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65
Q

What are fats broken down into?

A

Fatty acids and glycerol

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66
Q

How do you test for fats?

A

Using the ethanol test

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67
Q

How do you test for protein?

A

Using the biuret test

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68
Q

How do you test for sugar?

A

Using Benedict’s test

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69
Q

What is the biuret test?

A

Sodium hydroxide and copper sulfate mixed together. Changes from blue to purple

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70
Q

What is Benedict’s test?

A

Add Benedict’s solution to the food and heat in a water bath. Changes from blue-black to brick red

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71
Q

What is the test for lipids?

A

Mix the fat with ethanol to dissolve some of it, then add it to water. Changes from clear to cloudy white

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72
Q

How do you calculate the energy released in Joules?

A

Mass of water x Rise in water temperature x 4.2

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73
Q

What is the experiment for calculating the energy in food? (5)

A
  • Hold a test tube in place suspended in the air, and fill it with 20cm3 of water.
  • Measure the temperature of the water using a thermometer and record this temperature.
  • Hold a piece of the food you are testing with a mounted needle, light it on fire using a bunsen burner and quickly hold it under the test tube.
  • When the food has fully burned, or will not burn anymore, measure the temperature again.
  • Calculate the temperature difference and use the equation to measure the energy released
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74
Q

What is an enzyme?

A

A protein that acts as a biological catalyst

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75
Q

What is a biological catalyst?

A

An enzyme that speeds up the rate of reactions in living organisms

76
Q

What is an enzyme’s active site?

A

The spot where the substrate fits perfectly into, and gets broken up

77
Q

What does it mean that an enzyme’s active site and the substrate are complimentary?

A

That the shape of the substrate fits perfectly into the active site of an enzyme

78
Q

What is enzyme specifity? (3)

A
  • Each enzyme is specific and will only work on its normal substrate
  • As its active site is complementary to the substrate
  • Forms an enzyme-substrate complex
79
Q

What are the substrate and products of carbohydrase?

A

Carbohydrates –> Glucose

80
Q

What are the substrate and products of amylase?

A

Starch –> Glucose

81
Q

What are the substrate and products of protease?

A

Protein –> Amino acids

82
Q

What are the substrate and products of lipase?

A

Fat –> Glycerol & fatty acids

83
Q

How does temperature affect enzyme activity? (4)

A
  • As the temperature increases, so does the chemical and kinetic energy of the enzymes so there is more enzyme activity and collisions
  • until the optimum temperature,
  • after which enzyme activity will slow due to enzyme denaturation,
  • eventually ceasing completely
84
Q

What is enzyme denaturation and how does it occur?

A

Above the optimum temperature (or both above and below it’s optimum pH) for enzyme activity, the enzyme’s active site will undergo an irreversible change that results in the substrate no longer fitting into the active site

85
Q

How does pH affect enzyme activity? (3)

A
  • At an enzyme’s optimum pH, the activity of the enzyme is at it’s greatest rate,
  • however if the pH increases or decreases,
  • enzyme activity decreases (Due to enzyme denaturation)
86
Q

How do you investigate the effect of temperature on enzyme activity?

A

In the case of the starch test:

  • Set up different water baths at regular intervals of temperature and fill a number of test tubes with 5cm3 of starch,
  • and the same number of test tubes with 5cm3 of amylase.
  • Place them both in the water bath at the same time and wait until they reach the right temperature.
  • Set up a spotting tile with a drop of iodine solution in each.
  • Mix the 2 solutions together in a small beaker and quickly take a sample and place it in a dimple in the tile.
  • Repeat this step at regular intervals until the iodine no longer turns blue-black.
  • Repeat this for all the different temperatures

At whichever temperature it takes the least amount of time for a colour change to occur, the enzyme activity is at it’s fastest rate

87
Q

What are the colour changes in hydrogen carbonate indicator?

A
  • Red in atmospheric levels of CO2 (0.04%)
  • Purple below atmospheric levels of CO2
  • yellow above atmospheric levels of CO2
88
Q

What is the definition of Digestion? (2)

A
  • The breakdown of large, complex, insoluble molecules into smaller, simple and soluble molecules
  • due to enzyme action
89
Q

What are thermostable enzymes? Where are they found?

A

Enzymes which work at a wide range of temperatures without becoming denatured

Usually found in commercial products like bio washing powder

90
Q

How is the structure of the ileum adapted for absorbing the products of digestion? (6)

A
  • it is long (~3 meters long)/is folded/contains villi/contains microvilli
  • it has a large surface area
  • it has a good blood supply
  • it maintains a diffusion gradient
  • it has thin/permeable membranes
  • it has a short diffusion pathway
  • the lacteal
  • absorbs fats/fatty acids and glycerol and returns them to the blood later

All are needed for full marks (1 of each with /)

91
Q

What is the shape of a graph displaying the effect of concentration on enzyme activity? (3)

A
  • The enzyme activity increases as enzyme activity increases,
  • until a certain point when other factors become limiting (e.g. substrate concentration)
  • and the graph levels off
92
Q

What is the word and symbol equation for aerobic respiration in humans?

A

Glucose + Oxygen –> Carbon Dioxide + water + energy
C6H12O6 + 6O2 –> 6CO2 + 6H2O + energy

93
Q

What is the word equation for anaerobic respiration in human muscles?

A

Glucose –> lactic acid + energy

94
Q

What is the word equation for anaerobic respiration in yeast?

A

Glucose –> Alcohol + Carbon dioxide + energy

95
Q

What do the different cells in the body use the energy released in respiration for? (5)

A
  • Movement,
  • growth,
  • reproduction,
  • active transport and
  • heat
96
Q

Is respiration an exothermic or endothermic reaction?

A

Exothermic because it releases energy

97
Q

How do you investigate the effect of temperature on the respiration of yeast?

A
  • Mix 3g of yeast with 4g of glucose with 100cm3 of boiled and cooled water in a beaker
  • Leave at room temperature for an hour
  • Fill a small test tube with this mixture
  • Place a boiling tube upside down over the small test tube and quickly invert both tubes
  • Place the tubes in a water bath at a temperature of 10°C
  • Measure the height of the bubble at the top of the inner, small tube
  • Repeat at various temperatures
  • After 30 minutes, measure the height of the bubble at the top of each of the inner tubes and calculate the change in height
98
Q

Explain the steps involved in the experiment demonstrating anaerobic respiration in yeast

A
  • a solution of glucose is first boiled to remove any dissolved oxygen and to sterilise it
  • yeast cells are added to this solution only after it has cooled
  • the solution of glucose with yeast is then placed in the apparatus
  • a layer of oil must be added above the solution to prevent oxygen entering
  • have a tube linking the test tube with another test tube containing limewater
  • if the test tube turns milky, CO2 is present and anaerobic respiration has occured
99
Q

How is energy used in the body?

A
  • growth and repair
  • reproduction
  • active transport
  • movement
  • production of heat (for homeostasis)
100
Q

How do you investigate the effect of different sugars on the respiration of yeast? (8)

A
  • Mix 3g of yeast with 4g of glucose with 100cm3 of water in a beaker
  • Leave at room temperature for an hour
  • Fill a small test tube with this mixture
  • Place a boiling tube upside down over the small test tube and quickly invert both tubes
  • Place the tubes in a water bath at a temperature of 30°C
  • Measure the height of the bubble at the top of the inner, small tube
  • Repeat with different sugars
  • After 30 minutes, measure the height of the bubble at the top of each of the inner tubes and calculate the change in height
101
Q

Name each part of the pathway in the respiratory system

A
  • trachea
  • bronchi
  • bronchioles
  • alveoli
102
Q

Why do the trachea and bronchi contain rings of cartilage?

A

To prevent each collapsing

103
Q

What is the name given to the layer of muscle separating the lung from the abdomen?

A

The diaphragm

104
Q

Where are pleural membranes located and what is their function?

A
  • The outer part of the lungs
  • they prevent friction between the lungs and rib cage
105
Q

What is contained within pleural membranes?

A

Pleural fluid

106
Q

What is between each of the rib bones

A

Intercostal muscles

107
Q

How are alveoli adapted for respiration? (6)

A
  • very large surface area (due to millions being in each lung)
  • the cells are moist between alveoli and capillaries (making them permeable)
  • only two layers of cells between alveolus and blood, making diffusion distance very short
  • good blood supply increases surface area for diffusion while maintaining high diffusion gradient
  • blood returning to lungs is low in oxygen and high in carbon dioxide, increasing diffusion gradient
  • diffusion gradients maintained by breathing (removing carbon dioxide and bringing oxygen in)
108
Q

What are the main respiratory surfaces in plants?

A

Spongy mesophyll cells

109
Q

How are spongy mesophyll cells adapted for respiration? (2)

A
  • there are lots of cells in contact with the air spaces, creating a large surface area
  • their cell membranes are thin, moist and permeable
110
Q

Explain the process of breathing in animals.

A

(Inhaling)
- intercostal muscles contract causing the ribs to move up and out
- diaphragm contracts and moves down
- the volume of the thorax increases and the pressure inside decreases
- air enters the lungs

(Exhaling)
- intercostal muscles relax and move down and in
- diaphragm relaxes and returns to it’s domed shape (up)
- volume of the thorax decreases and the pressure inside increases
- air leaves the lungs

111
Q

What is the name given to the time taken for the breathing rate to return to normal?

A

Recovery time/rate

112
Q

How would a fit person’s breathing rate compare with an unfit person’s?

A

They (fit person) would have:
- a lower resting breathing rate
- a slower rate of increase in breathing rate during exercise
- a lower maximum breathing rate
- a faster recovery rate

113
Q

Explain the effect of exercise on breathing (4)

A
  • exercise requires the movement of muscle cells which requires energy, this is increased during exercise
  • aerobic respiration requires oxygen, therefore as more energy is used by the body, more air is inhaled
  • this means more CO2 in the bloodstream, which means more air must be inhaled and exhaled to remove it
  • the person will breathe with increased speed and depth to inhale more air and subsequently oxygen for aerobic respiration
114
Q

Where is the respiratory system located in the body?

A

The Thorax (The chest cavity)

115
Q

What is the thorax surrounded by?

A

Ribs of bone with intercostal muscles between them

116
Q

What is the structure below the thorax?

A

The diaphragm, a muscular sheet that can move up and down

117
Q

Where does air enter the body and where does it go?

A

Air enters through the nasal cavity where it is warmed and filtered before continuing into the lungs via the trachea

118
Q

Where does gas exchange take place in humans?

A

The alveoli

119
Q

What is the diaphragm represented by in the bell jar lung model?

A

A rubber sheet

120
Q

What is the thorax represented by in the bell jar lung model?

A

The bell jar

121
Q

What are the lungs represented by in the bell jar lung model?

A

Balloons

122
Q

Explain how the bell jar lung model demonstrates the process of breathing

A

Inhaling
- As the rubber sheet (diaphragm) moves down, the volume inside the jar increases.
- This causes the pressure inside the jar to decrease and as a result, air enters the balloons (lungs) until the pressures inside and outside the jar are equal.

Exhaling

  • As the rubber sheet (diaphragm) moves up, the volume inside the jar decreases.
  • This causes the pressure inside the jar to increase and as a result, air exits the balloons (lungs) until the pressures inside and outside the jar are equal.
123
Q

How does the bell jar lung model fail to accurately represent how breathing takes place in humans? (2)

A
  • There is no representation of the ribs moving up and out for inhaling and down and in for exhaling.
  • The thorax is much smaller in reality than in the bell jar lung model
  • the diaphragm is, in actuality a domed shape before contracting, becoming straight
124
Q

What is a stimulus?

A

Anything that we respond to/triggers an impulse

125
Q

What does an effector affect?

A

A receptor

126
Q

What happens when a receptor is stimulated?

A

It causes an effector to produce a response

127
Q

What are receptors and effectors connected by?

A

A coordinator, usually the brain but may also be the spinal cord

128
Q

What are the brain and spinal cord known as?

A

The central nervous system

129
Q

What links the receptors and effectors to the coordinators?

A

Nerve cells or neurones

130
Q

What do neurones carry information as?

A

Small electrical charges called nerve impulses

131
Q

How are neurones adapted? (3/4)

A

(+ - They have a nucleus that controls the activities of the neurone)
- They have long axons so that nerve impulses can be carried across long distances throughout the body
- They have a fatty layer called the myelin sheath that acts as an insulator that helps to speed up the nerve impulses
- The branched ends of the axon allow the neurone to make junctions with other nerve cells

132
Q

What is a synapse?

A

The junction between two neurones

133
Q

How are nerve impulses transferred from one neurone to another? (4)

A
  • When an electrical impulse reaches the end of the axon, it causes (synaptic) vesicles to release a special chemical called the transmitter substance/neurotransmitter
  • which diffuses across the synapse to the neurone adjacent.
  • If the concentration of transmitter substance is high enough on the other side of the synapse, it triggers an electrical impulse on the axon leaving the junction
  • and the nerve impulse continues on its way
134
Q

What is a voluntary action?

A

An action we do deliberately that involves conscious thought

135
Q

What is a reflex action?

A

An action that does not involve conscious thought that happens automatically, like breathing or blinking

136
Q

What are the two main characteristics of a reflex action?

A

They occur:
- very rapidly and
- do not involve conscious control

137
Q

What makes reflex actions so rapid?

A

In a reflex pathway, the length of the pathway is kept as short as possible with the minimum number of neurones needed and as few synapses as possible

138
Q

What is a reflex arc?

A

The nerve pathway involved in a reflex action

139
Q

What is the sensory neurone?

A

The neurone that carries information from receptors

140
Q

What is the motor neurone?

A

The neurone that carries information from the spinal cord back to the effector, causing a response

141
Q

What is the association / connector / relay neurone?

A

The neurone that connects the sensory and motor neurone

142
Q

What does the iris do?

A

Controls how much light enters the eye

143
Q

What is the pupil?

A

The space in the iris through which light passes

144
Q

What is the cornea?

A

The transparent front part of the eye that allows light to enter the eye and causes some refraction

145
Q

What is the aqueous humour?

A

The transparent, incompressible watery liquid that helps focussing and to maintain the eye’s shape

146
Q

What is the conjunctiva?

A

The thin, transparent, protective outer covering of the eye

147
Q

What is the retina?

A

The inner coat of the eye where light-sensitive cells are found

148
Q

What is the lens?

A

The transparent, dome shaped part of the eye which refracts light onto the retina

149
Q

What is the vitreous humour?

A

Jelly-like substance that helps maintain the shape of the eye and keeps the retina against the wall of the eye

150
Q

What is the optic nerve?

A

Nerve that contains neurones carrying information to the brain

151
Q

Where is the blind spot?

A

Where the optic nerve creates a gap in the retina

152
Q

What is the suspensory ligament?

A

Ring of strong fibres supporting the lens that stretch and slack to allow different amounts of light to enter the eye

153
Q

What are the ciliary muscles?

A

Ring of muscles that pull on the suspensory ligament to change the shape of the lens and allow different amounts of light into the eye

154
Q

How does the eye focus on a distant object?

A

The ring of ciliary muscles relaxes, suspensory ligaments stretch and the lens is thin

155
Q

How does the eye focus on a nearby object?

A
  • The ring of ciliary muscles contracts,
  • suspensory ligaments slack
  • and the lens is thick
156
Q

Why is controlling the amount of light entering the eye important?

A

If too little or too much light enters the eye and reaches the retina, it can damage the sensitive light receptor cells in the retina

157
Q

What happens to the pupil in dim light?

A

The size of the pupil is increased to allow more light to enter the eye

158
Q

What happens to the pupil in bright light?

A

The size of the pupil is decreased to restrict the amount of light entering the eye

159
Q

What is negative feedback?

A

Negative feedback is a homeostatic mechanism in which conditions are returned to the ideal or set point after conditions have deviated from this set point

160
Q

What does insulin do to blood glucose concentration?

A

It limits the concentration

161
Q

Where is insulin produced and released?

A

The pancreas

162
Q

What causes insulin to be produced?

A

In response to increasing or high blood glucose concentrations

163
Q

What does insulin achieve?

A

The prevention on the concentration of glucose in the blood becoming too high

164
Q

Why does the concentration of glucose in the blood need to be limited?

A

Too much glucose can damage body cells due to water loss

165
Q

What is the main target organ for insulin and why?

A

The main target organ for insulin is the liver where it causes:
– Increased absorption of glucose from the blood, reducing blood glucose concentration;
– The conversion of excess glucose into glycogen which is stored in the liver
– Increased respiration

166
Q

What is a hormone?

A

A chemical message produced by special glands which release them into the blood

167
Q

What is the organ that a hormone affects called?

A

The target organ

168
Q

What is homeostasis?

A

Keeping the body in a constant state in response to changes outside and inside the body

169
Q

What is osmoregulation?

A

A homeostatic process that controls the amount of water in the blood and other body fluids

170
Q

What is diabetes?

A

A condition in which the body does not produce enough insulin to keep the blood glucose at the normal concentration

171
Q

What 3 ways does the body gain water?

A
  • Drinking liquids
  • in food
  • water as a product from respiration
172
Q

How does the body lose water?

A
  • evaporation of sweat
  • breathing out water vapour
  • in urine
173
Q

Give the steps taken by the body when blood is too dilute

A
  • blood concentration normal
  • large drink of liquid
  • blood too dilute
  • kidney reabsorbs less water back into blood and more urine is produced (LESS ADH)
174
Q

Give the steps taken by the body when blood is too concentrated

A
  • blood concentration normal
  • lots of water lost (eg sweat during exercise)
  • blood too concentrated
  • kidney reabsorbs more water back into blood and less urine is produced (MORE ADH)
175
Q

What is ADH? Where is it produced and what is it’s target organ?

A

ADH (anti diuretic hormone) is a hormone which controls how much water the kidney reabsorbs

It is produced in the brain and it targets the kidneys

176
Q

What blood vessel supplies the kidney?
What blood vessel exits the kidney?

A
  • The renal artery (supplies blood for filtering)
  • the renal vein (returns filtered blood to the vena cava)
177
Q

Name each part of the kidney (at this level obvs)

Also

Name the other parts of the excretory system

A
  • renal pelvis
  • medulla (middle part of the kidney)
  • cortex (outer part of kidney)

Other parts of excretory system

  • ureter (tube to bladder)
  • bladder
  • sphincter muscle (holds urine in bladder)
  • urethra (take urine out of the body)
178
Q

What is phototropism?

A

The growth response by plants in which they grow in the direction of light

179
Q

Why does phototropism occur?

and

how does it work?

A

Phototropism occurs when a plant receives light from one direction (unilateral)

It works as auxin (a hormone) is released from the tip of the plant and travels disproportionately to the shaded part of the plant (it travels in such a way due to the direction from which the tip receives light).

More auxin is on the shaded part of the plant, causing the plant to grow more on this side and therefore, bend toward light

180
Q

Give one similarity and one difference between human and plant stem cells (2)

A

Similarity:

cells divide/mitosis/differentiate;

Difference:

plant stem cells can redifferentiate;
human stem cells cannot redifferentiate;

181
Q

Why are stem cells useful in medicine? (2)

A
  • ability to divide
  • to produce cells of one/same type
182
Q

What is the function of the lacteal? (2)

A
  • Absorbs breakdown products of lipids (glycerol and fatty acids)
  • and returns them to the blood later
183
Q

What is calcium used for in plants?

A

Helps produce cellulose for structural support

184
Q

What is magnesium used for in plants?

A

Helps produce chlorophyll

185
Q

What are nitrates used for in plants?

A

Production of proteins

CCEA GCSE (S1) (25 decks)

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