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Biology P1 Flashcards

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1
Q

What does an electron microscope allow you to do?

A

Allow you to visualise finer details including organelles (sub-cellular structures) due to their greater resolving power and higher resolution

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2
Q

What is the difference between eukaryotic and prokaryotic cells?

A

Eukaryotic cells have a membrane-bound nucleus, and prokaryotic cells don’t

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3
Q

What is the cell membrane used for?

A

It controls what enters and leaves, semi-permeable (allow certain substances to pass through)

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4
Q

What is a cell wall for and what is is made of?

A

Its to provide a rigid structure, made out of cellulose

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5
Q

What is cytoplasm?

A

The liquid that makes up the cell, where most chemical reactions take place

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6
Q

What are mitochondria?

A

Where respiration takes place, providing the cell with energy

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7
Q

What are ribosomes?

A

Where proteins are assembled/synthesised

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8
Q

What are chloroplasts?

A

They contain chlorophyll which is where photosynthesis takes place

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9
Q

What’s a permanent vacuole?

A

Where sap is stored

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10
Q

How many chromosomes are in a human cell?

A

23 pairs of chromosomes (diploid) , except gametes (sperm/eggs) that have just 23 (haploid)

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11
Q

What happens in Mitosis?

A
  1. Genetic material is duplicated
  2. The nuclear membrane dissolves
  3. The two sets of chromosomes line up along the centre of the cell
  4. Both sets of chromosomes are pulled to opposite ends of the cell
  5. New nuclei are formed (or ‘the nucleus divides’)
    Other organelles are also duplicated, and the cell divides, producing two genetically identical diploid cells
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12
Q

What are stem cells and where are they found?

A

Stem cells can specialise into different cells to perform specific functions
They are found in animal embryos and plant meristems

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13
Q

What’s the difference between embryo stem cells and adult stem cells?

A

Adult stem cells are made in your bone marrow, but they can only specialise into blood cells

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14
Q

What is diffusion?

A

The movement of particles from an area of high concentration to that of a low concentration, this is passive as it requires no energy

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15
Q

What is osmosis

A

The diffusion of water across a semi-permeable membrane to balance the concentrations of solution inside and outside a cell. Water must move, as larger molecules cannot fit through the holes. Water moves in if the concentration is higher outside

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16
Q

How can we increase the rate of diffusion and osmosis?

A
  • Increasing the difference in concentrations
  • Increasing the surface area
  • Increasing the temperature
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17
Q

What is the osmosis practical?

A
  1. Weigh and place identical cylinders from same vegetable in sugar solutions of varying concentrations
  2. After set time, remove excess water and reweigh, calculate % change in mass (final mass - initial mass)/ initial mass x 100
  3. Plot % change in mass against concentration. Using the line of best fit, the concentration at 0% change in mass is the same as inside the vegetable
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18
Q

What is active transport?

A

The movement of particles through a membrane via carrier proteins. This requires energy, and so can move them against the concentration gradient

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19
Q

What is the role of teeth in the digestive system?

A

Teeth break down food mechanically; saliva contains amylase

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20
Q

What is the role of the stomach in the digestive system?

A

The stomach contains hydrochloric acid and contains enzymes (pepsin) that chemically break down the food

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21
Q

Where is bile produced and where is it stored?

A

The liver produces bile, which is stored in the gall bladder

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22
Q

What is the role of bile in the digestive system?

A

Bile emulsifies lipids to form droplets, increasing their surface area. Also neutralises the acid from your stomach

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23
Q

What is the role of the pancreas in the digestive system?

A

The pancreas secretes amylase which breaks down starch into glucose in the small intestine

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24
Q

What is the role of the small intestine in the digestive system?

A

Nutrients like glucose are absorbed into the bloodstream by the villi in the small intestine

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25
What is the role of the large intestine in the digestive system?
Water is absorbed into the bloodstream
26
What are enzymes?
Enzymes are special proteins that act as biological catalysts, often breaking down molecules into shorter ones (polymers into monomers)
27
What do carbohydrase, amylase, protease and lipases break down?
Carbohydrase - Break down carbohydrates into simple sugars Amylase - Break down starch into glucose Protease - Break down proteins into amino acids Lipase - Break down lipids into glycerol and fatty acids
28
What is the effect on enzyme activity with an increase in temperature?
The rate of reaction increases with temperature, this it is too hot and the enzymes denature (active site changes shape). The same is true for too high or low pH
29
What is the enzyme practical?
1. Mix amylase with starch and start timer 2. Remove a few drops every 10 seconds and add to iodine 3. Record the time taken for no starch to be detected (iodine will remain orange) 4. Repeat at different temperatures or with a different pH buffer solutions added 5. Plot these times against temperature/ pH on a graph, draw a line of best fit, find the optimum temperature/ pH (between the two lowest times)
30
What is the food test for starch?
Starch turns IODINE from orange to black
31
What is the food test for protein?
Protein turns BIURET'S REAGENT turns blue to purple
32
What is the food test for sugars?
Sugar turns BENEDICT'S SOLUTION from blue to green, yellow, orange or red depending on the concentration of the sugar
33
What is the food test for lipids
Lipids turn COLD ETHANOL from transparent to cloudy
34
What is the order in which air moves through our body?
1. Down the trachea 2. Into the bronchi 3. Then into the bronchioles 5. Ends up in the alveoli where it diffuses into the blood vessels around it
35
What are the adaptations of alveoli?
Bumpy - large surface area to allow gas exchange to occur at a fast rate Thin walls Rich blood supply
36
What happens to the oxygen after the alveoli?
It diffuses into the bloodstream and binds to the haemoglobin in red blood cells to be transported around the body
37
What is the journey for deoxygenated blood in the heart?
Enters through the vena cava into the right atrium, where there is a valve to the right ventricle. The heart muscles contract and it goes through the pulmonary artery to the lungs to be oxygenated
38
What is the journey for oxygenated blood in the heart?
Enters through the pulmonary vein from the lungs, then to the left atrium, then left ventricle before the muscle contracts and pumps it out the aorta to be transported around the body.
39
Why does one side of the heart have thicker walls?
The left side has thicker walls due to the higher pressure needed to pump blood to the body rather than just the lungs
40
What causes the heart to contract?
A group of cells in the walls of the right atrium create electrical pulses that causes the heart to contract, can use artificial pacemakers if not working
41
What are the difference between veins and arteries?
Artery carries blood away from the heart, veins carry blood back to the heart Arteries have thick walls and thin lumen to withstand high pressure, veins have thin walls and wide lumen Veins also have valves to prevent backflow which can be replaced with artificial ones if faulty
42
What are capillaries?
Arteries split and get smaller until they end up as capillaries, which have one thick cell wall to allow fast diffusion between blood and cells
43
What is CHD (Coronary Heart Disease)?
When the artery supplying blood to the heart becomes blocked by the build up of fatty deposits, restricted blood flow to the heart
44
What are stents?
They can be inserted into blood vessels to keep them open, so blood can flow
45
What are statins?
Drugs that reduce cholesterol which in turn reduce the fatty deposits
46
What is a non-communicable disease?
The cause comes from inside the body, cannot be spread to other people
47
What is a communicable disease?
Caused by pathogens that enters your body, causing a bacterial, viral or fungal infection
48
What is a carcinogen?
Anything that increases the risk of cancer
49
What's the difference between benign and malignant cancers?
Benign does not spread, malignant spreads through the body
50
What are xylem?
Continuous tubes that carry water and dissolved mineral ions upwards in plants
51
What are the purposes of leaves?
Where photosynthesis happens and water evaporates out via transpiration
52
What are the purpose of roots?
Where water enters through osmosis, mineral ions by active transport
53
What is the purpose of flowers?
Where the reproductive organs are
54
What are meristems?
Where stem cells are produced (n plants
55
What are phloem?
Tubes of cells that carry sugars and other nutrients to where needed: Translocation - bidirectional
56
What is the waxy cuticle?
The top layer of the leaf, its waterproof to stop water loss
57
What is the upper epidermis?
The second layer of the leaf, transparent cells that let light through
58
What is the palisade mesophyll?
The third layer of the leaf, full of chloroplast, where photosynthesis takes place
59
What is the spongey mesophyll
The fourth layer of the leaf, lots of gaps around the cells to increase the surface area, form which gas exchange occur - Carbon dioxide diffuse into the cell while water and oxygen diffuse out
60
What is the vein/vascular bundle?
In the middle of the spongey mesophyll, contains the xylem and phloem
61
What is the lower epidermis?
Bottom of the leaf, contains stomata which is how gases exit and enter the leaf
62
What are stomata?
Holes in lower epidermis to allow gases in/out, including water. The size of the holes are controlled by guard cells, they change size to control the rate at which gases are exchanged
63
What is a pathogen?
A micro-organism that causes disease: bacteria, viruses, fungi, protists
64
What is a virus?
A protein casing that surrounds genetic code that it injects into a cell that makes the cell produce more copies of the virus, the cell explodes and the viruses repeat with other cells
65
2 examples of viruses?
Measles, HIV
66
What do bacteria do in your body?
They release toxins into your body that damage cells
67
2 examples of bacteria?
Salmonella, gonorrhoea
68
2 examples of plant diseases?
Rose black spot, Tobacco mosaic virus
69
What methods of defence do our bodies and plants have against pathogens?
Human - Skin stops, mucus in nose/trachea traps, acid & enzymes kill pathogens. Plants - Cell wall, waxy cuticle & bark are barriers; antibacterial chemicals; poison/thorns to deter other organisms
70
What is a lymphocyte?
A type of white blood cell that produces antitoxins to neutralise toxins made by pathogens, and antibodies that bind to the antigen of a pathogen, but only if they fit. These stop viruses from infecting cells, and cause them to clump together
71
What is a phagocyte?
A type of white blood cell that will engulf pathogens
72
What is a vaccine?
A dead/inert version of a virus, so you can gain immunity without you becoming ill
73
What are antibiotics?
They kill bacteria, but not viruses. Bacteria can become resistant to antibiotics
74
What is the word equation for photosynthesis?
Water + Carbon Dioxide --> Glucose + Oxygen
75
What is the balanced chemical equation for photosynthesis?
6H20 + 6CO2 --> C6H12O6 + 6O2
76
Is photosynthesis endothermic or exothermic?
Endothermic as sunlight is needed
77
What is the glucose used for in photosynthesis?
Respiration Making starch/fat to store energy Making cellulose Making amino acids for proteins
78
What increases the rate of photosynthesis?
Increasing temperature Increasing light intensity Increasing CO2 concentration
79
What is the practical for measing rate of photosynthesis?
1. Cut pondweed stem, put in inverted measuring cylinder filled with water (add sodium hydrogen carbonate to provide CO2) 2. Let acclimatise first, then measure volume of oxygen made in e.g. 1 minuet (or count bubbles, less accurate) 3. Repeat at different distances from light source
80
What is the word equation for aerobic respiration?
Glucose + Oxygen --> Water + Carbon Dioxide (opposite of photosynthesis)
81
What is the word equation for anaerobic respiration?
Glucose --> Lactic acid
82
What is the word equation for anaerobic respiration in plants?
Glucose --> Ethanol + Carbon dioxide (aka fermentation)
83
What is metabolism?
The sum of all chemical reactions in a cell/organism

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