Alexandros Tricky Topics Flashcards
(113 cards)
1
Q
Diameter of mitochondria
A
0.2-0.7μm
2
Q
Length of mitochondria
A
1-2 μm
3
Q
Diameter of a nucleus
A
10 μm
4
Q
Length of chloroplasts
A
3-5 μm
5
Q
Length of prokaryotes
A
0.2-2.0 μm
6
Q
Length of eukaryotic cells
A
10-100 μm
7
Q
What is at the end of the head of a sperm cell?
A
Acrosome
8
Q
Specialisation in nerve cells?
A
Lots of dendrites to make connections to other nerve cells.
Axon carries the nerve impulse from one place to another, very long.
Synapses are adapted to passing impulses to other cells or between a nerve cell and a muscle in the body using special transmitter chemicals.
9
Q
Specialisation in muscle cells?
A
They contain special proteins that slide over each other, making the fibres contract.
They contain many mitochondria to transfer the energy needed for the chemical reactions that take place as the cells contract and relax.
They can store glycogen, a chemical that breaks down and is used in cellular respiration by mitochondria to transfer energy for the fibres to contract.
10
Q
Specialisation in sperm cells?
A
A long tail to help the sperm swim through the female reproductive system.
Middle section is full of mitochondria for transferring energy for the tail to work.
The acrosome stores digestive enzymes for breaking down the outer layers of the egg.
A large nucleus contains the genetic material to be passed on.
11
Q
Specialisation of root hair cells?
A
Hairs greatly increase the surface area available for water to move into the cell.
The large permanent vacuole speeds up movement of water by osmosis from the soil across the root hair cell.
They have many mitochondria to transfer the energy needed for the active transport of mineral ions into the root hair cells.
12
Q
Specialisation of photosynthetic cells?
A
Chloroplasts trap light for photosynthesis.
Positioned in continuous layers of leaves and outer layers of the stem of a plant to absorb more light.
They have a large permanent vacuole to keep the cell rigid as a result of osmosis.
When all arranged together, they form photosynthetic tissue, supporting the stem, and keep the leaf spread out so it can capture light easily.
Contains chloroplasts with chlorophyll, to capture light for photosynthesis.
13
Q
Specialisation of xylem cells?
A
They form the chemical lignin which spirals in the cell walls. They cells die and form long hollow tubes for water and mineral ions to pass through from one end of the plant to the other.
The spirals and rings of lignin in the xylem cells make them very strong and help them withstand the pressure of water moving up the plant. They also support the plant stem.
14
Q
Specialisation of phloem cells?
A
The cell walls between cells break down to form special sieve plates, allowing water carrying dissolved food to move freely up and down the tubes to where it’s needed.
Phloem cells lose a lot of their internal structure but are supported by companion cells to keep them alive, containing mitochondria, producing energy needed to move dissolved food up and down the plant in phloem.
15
Q
What is the net movement?
A
Particles moving in - particles moving out
16
Q
How is oxygen used in diffusion in cells?
A
Cells need oxygen for respiration (mitochondria), and cells surrounded with oxygen (high concentration), transporting oxygen from the lungs into the bloodstream.
Then, oxygen is used to generate energy in respiration, and produces carbon dioxide. There is a higher concentration of carbon dioxide inside the cell, so the carbon dioxide moves out.
17
Q
How is urea used in diffusion in cells?
A
Urea (waste product produced in cells) diffuses out of the cells into the blood plasma and is secreted by the kidneys.
18
Q
Factors affecting diffusion?
A
Concentration gradient
Temperature (gives kinetic energy)
Surface area (folds in cell lining)
19
Q
Isotonic
A
Concentration is the same inside and outside the cell
20
Q
Hypertonic solution
A
More concentrated outside than inside the cell.
21
Q
Hypotonic solution
A
More concentrated inside than outside the cell.
22
Q
Osmosis in animal cells
A
The cell will die if place in extreme conditions, so it’s extremely concentrated outside or inside to cause the cell to shrivel up/burst.
23
Q
Equipment for osmosis RP
A
Cork borer Potato Balance Knife Test tube Measuring cylinder Distilled water Label/pen to label each test tube Various concentrations of sucrose Paper towel to dry potato Ruler Sieve
24
Q
What is an appropriate way to measure the effect of osmosis on a potato?
A
Measure starting and current mass and calculate percentage change.
25
What happens when we increase the concentration of sugar outside the potato?
The gain in mass decreases-there are less water particles.
26
How do plants use osmosis?
It's supports their stems and leaves. Water moves into cells by osmosis until no more can enter, known as turgor pressure. They rely on hypotonic fluids surrounding the cell, keeping the cell turgid. If it's hypertonic to the cell contents, water will leave the cell and the cell becomes plasmolysed and dies if osmotic balance is not restored.
Turgid>Flaccid>Plasmolysed
27
Use of active transport in the body
Glucose is needed for cell respiration, getting as much as possible from the gut. The concentration of glucose in the bloodstream is kept stead, so sometimes it's higher than the concentration in the gut, moving the glucose from the gut into the blood, against the concentration gradient.
28
Use of active transport in plants
Mineral ions in the soil are found in very dilute solutions (more dilute than the solution in root hair cells), so the cells absorb the mineral ions, against the concentration gradient.
29
How are fish adapted for surface area:volume (diffusion)?
The filaments give the gills a massive surface area, also having a thin membrane to provide a short diffusion pathway.
The filaments have an efficient blood supply to take the oxygenated blood away, ensuring the concentration gradient is always high.
30
What is the problem with having a small surface area : volume ratio?
Gases and food molecules can't reach every cell.
| Metabolic waste cannot be removed quick enough to avoid cell poisoning.
31
Mitosis stages
The longest part is when chromosomes are replicated in the nucleus.
Then, the nucleus divides, and chromosomes are push to each end of the cell.
Finally, the cell divides into 2 daughter cells.
32
What is the purpose of mitosis?
To replace old cells to repair damaged tissue.
| To help organisms grow.
33
Problems with bone marrow transplants
The donor's bone marrow has to be compatible with the patient, otherwise, the white blood cells produced by the donated bone marrow could attack the patient's body.
There is a risk of passing viruses from the donor to the patient.
34
Why is therapeutic cloning better than bone marrow transplants?
An embryo produced uses the same genes as the patient, without being rejected by the patient's immune system.
35
How do plants clone/produce stem cells?
Roots and buds contain meristem tissue, and these stem cells can differentiate into any type of plant tissue.
We can clone plants, stopping them from going extinct, or we could produce cloned crop plants for farmers.
36
Problems with embryonic stem cells
They come from aborted embryos, or spare embryos from fertility treatment. It's basically killing a human.
Slow, difficult, expensive procedure. It's hard to make embryonic stem cells to differentiate into the type of cell needed.
They divide and grow rapidly-it could cause cancer if used to treat people.
Could transfer viruses, the patient may take drugs to prevent it.
37
Where else can embryonic stem cells be found?
In the umbilical cord blood of newborn babies.
| Amniotic fluid surrounding the foetus.
38
What is therapeutic cloning?
When an adult produces a cloned early embryo of themselves.
39
Why does the length of the cell cycle differ for various cells?
Cell cycles shorten as you grow older, because they may not be used for growth, only repair.
40
Tissue
A group of cells with similar structure and function.
41
Organ
A group of tissues working together for a specific function.
42
Give an example of an organ.
The stomach, containing muscle tissue and glandular tissue (which releases enzymes).
43
Organ system
A group of organs working together to form organisms.
44
The mouth
Contains salivary glands, teeth and the tongue. Teeth grind the food, and the salivary glands produce enzymes to break down the nutrients into smaller molecules.
45
Oesophagus
The tube the food passes down into the stomach.
46
Stomach
Where the digestion of proteins begin (by enzymes). Contains hydrochloric acid, which helps the enzymes digest proteins. The stomach muscles churn the food into a fluid, increasing the surface area for enzymes to digest.
47
Small intestine
Where the fluid from the stomach is passed onto. Chemicals are released. Soluble food molecules are absorbed into the blood. It's covered in villi, giving it a big surface area, and it has a short diffusion distance to blood vessels, as well as having a good blood supply, greatly increasing diffusion and active transport rate to the blood.
48
Pancreas
Releases enzymes which continue the digestion of starch and protein, and they start the digestion of lipids.
49
Liver
Releases bile which helps speed up digestion of lipids, also neutralising acid released from the stomach. Bile travels along the bile duct.
50
Large intestine
Where water is absorbed into the bloodstream.
51
What are the products of digestion uses in the body?
They build new carbohydrates, lipids and proteins, and some of the glucose produced is used in respiration.
52
Method for food tests, carbs
Grind, cut samples with pestle and mortar.
Put the sample into the beaker, adding distilled water.
Filter the sample with a funnel and filter paper.
Add a sample with a pipette in each test tube.
Add benedict's solution to the sample (FOR CARBS) and place the test tube into a water bath.
If glucose is present, the colour will change (brick red last).
53
Method for food tests, starch
Grind, cut samples with pestle and mortar.
Put the sample into the beaker, adding distilled water.
Filter the sample with a funnel and filter paper.
Add a sample with a pipette in each test tube.
Add iodine to the test tube and place in a water bath.
If starch is present, the solution will turn blue/black.
54
Method for food tests, fat (lipids)
Grind, cut samples with pestle and mortar.
Put the sample into the beaker, adding distilled water.
Add a sample with a pipette in each test tube.
Add ethanol to the test tube and place in a water bath.
Place a bung and shake vigorously.
If lipids are present, a red-stained oil layer will separate and float on the surface.
55
Method for food tests, protein
Grind, cut samples with pestle and mortar.
Put the sample into the beaker, adding distilled water.
Filter the sample with a funnel and filter paper.
Add a sample with a pipette in each test tube.
Add Biuret to the test tube.
If protein is present, the solution changes to a pink/purple colour.
56
What is the structure of a lipid molecule?
A molecule of glycerol attached to three molecules of fatty acids
57
Why does bile speed up the digestion of lipids?
Because it emulsifies them, splitting them into liquid droplets, increasing the surface area.
58
Method for digestion of starch (amylase)
Put 2cm^3 of starch solution into a test tube, and do the same for different test tubes with the buffer solution and amylase.
Place all into a water bath, and monitor temperature with a thermometer until they reach 30°C.
Put them all into 1 test tube, keeping the test tube in a water bath.
Then, place iodine into a spotting tile, and every 30s, transfer the solution to each spot, and stop the timer as soon as the solutions no longer turn blue/black.
There you go...there is your approximate time.
59
Blood plasma transports:
Soluble digestion products from the small intestine to other organs.
Carbon dioxide from the organs to the lungs to be breathed out (aerobic respiration).
The waste-product urea from the liver to the kidneys to be excreted in urine.
60
Red blood cells transport:
Oxygen from the lungs to the body cells.
61
Red blood cell adaptations for its purpose:
They contain haemoglobin, which is a molecule that binds to oxygen.
No nucleus, more room for haemoglobin.
Biconcave disc for greater surface area for quicker diffusion rate of oxygen.
62
What is the role of white blood cells?
They form part of the immune system (producing antibodies, antitoxins, etc.).
63
What is the adaptation of white blood cells?
They contain a nucleus, which contains DNA, instructions for the white blood cells to do their job.
64
What is the role of platelets?
They help the blood to clot.
65
What use does donated blood have in medicine?
To replace blood lost during injury.
Some people are given platelets extracted from blood to help in clotting.
Proteins extracted from blood can also be useful for example antibodies.
66
What are the adaptations of the arteries?
They have thick muscular walls to withstand high pressure of blood.
Elastic fibres stretch when the surge of blood passes through and recoil in between surges, which keeps the blood moving.
67
What are the adaptations of capillaries?
They are very thin and narrow, allowing substances like glucose and oxygen to diffuse easily out of the blood, into the cells.
Carbon dioxide diffuses from the cells back into the blood.
68
Through what blood vessel does the blood travel to the heart (from organs)?
Through veins
69
Low pressure exists between the organs and the heart-what's the problem with this?
The blood flow could stop or even go backwards.
70
What are the adaptations of veins?
They have a thin wall, and it's ok because blood pressure is low between the organs and heart.
They also have valves to prevent blood from flowing backwards. The valves open when blood is flowing in the right direction.
71
What is the problem with a single circulatory system?
The blood loses a lot of pressure before reaching the organs, so the blood travels to the organs very slowly, which doesn't deliver a great deal of oxygen.
72
Why is there thicker muscle in the left ventricle?
Because it needs to pump blood around the body.
73
What is the purpose of coronary ateries?
They provide oxygen to the muscle cells of the heart. The oxygen used in respiration provides energy for contraction.
74
Where is the pacemaker located in the heart?
The right atrium
75
What are stents?
They are a metal mesh that are inserted into the coronary artery with a balloon, is inflated, then the balloon is removed with the stent still inside. They also release drugs that prevent blood clotting.
76
Why are the rings of cartilage needed in the trachea?
They prevent the trachea from collapsing during inhalation.
77
The order of gas exchange:
Trachea
Bronchi (into the lungs)
Bronchioles
Alveoli
78
What happens in the alveoli?
Gases diffuse in and out of the bloodstream.
79
How are alveoli adapted for gas exchange?
The millions of alveoli in the lungs provide a huge surface area.
The alveoli have very thin walls so the diffusion path is very short.
The alveoli have a very good blood supply.
Once the oxygen diffuses into the blood, it is rapidly removed, ensuring it keeps a steep concentration gradient.
80
How can we affect the rate of diffusion in our lungs?
By breathing-it brings fresh oxygen into the alveoli and takes away the carbon dioxide, keeping the concentration gradient high.
81
What is the adaptation of the upper epidermis?
It's transparent, allowing light to pass through to the photosynthetic cells below.
82
What does the waxy cuticle do?
It reduces the evaporation of water from the surface of the leaf, helping prevent leaves from drying out.
83
The lower epidermis has tiny pores called...
Stomata
84
What is the role of stomata?
They allow carbon dioxide into the leaf and oxygen to leave. They also control the amount of water vapour that can pass out of the leaf.
85
On either side of the stomata, there are...
Guard cells
86
What is the palisade mesophyll made of?
Palisade cells, full of chloroplasts, containing chlorophyll, absorbing light energy needed for respiration.
87
Why is the spongy mesophyll full of air spaces?
They allow carbon dioxide to diffuse from the stomata through the spongy mesophyll to the palisade cells.
Oxygen also diffuses from the palisade cells, through the spongy mesophyll to the stomata.
88
What is the role of xylem tissue in a plant?
It transports water from the roots to the stem and leaves.
| It also transports dissolved mineral ions (including magnesium which is used to make chlorophyll).
89
What is the role of phloem tissue?
It transports dissolved sugars produced by photosynthesis from the leaves to the rest of the plant. Glucose is used immediately in respiration, or sugars can be stored as starch.
90
Translocation is...
The movement of sugars and other molecules through phloem tissue.
91
Transpiration stream
Starts with the evaporation of water from cells inside the leaf.
The water vapour then diffuses through the air spaces in the spongy mesophyll and out of the stomata.
Now water from the xylem replaces the water lost.
Water is finally drawn into the root hair cells and up the xylem vessels to the leaf.
92
What does the transpiration stream do?
Transports dissolved mineral ions (such as magnesium) and water.
Evaporates water to cool the leaf down.
93
Factors affecting transpiration:
Temperature-because evaporation rate is higher at higher temperatures.
Dry conditions, when the air is not humid-evaporation takes place more quickly under dry conditions.
Windy conditions-wind removes water vapour, allowing more water to evaporate.
Light intensity-high light intensity increases the rate of photosynthesis.
94
Properties of stomata, conditions
Surrounded by two guard cells, which swell during the day and change their shape, causing the stomata to open, allowing carbon dioxide to diffuse into the lead and be used in photosynthesis.
95
Name 3 viral diseases.
Tobacco mosaic virus
HIV/AIDS
Measles
96
What are the symptoms of measles?
Causes blindness and brain damage, could be fatal.
97
What are the symptoms of Tobacco mosaic viruses (TMV)?
It causes a mosaic pattern to form on the leaves, cells are destroyed. Affected areas don't photosynthesise.
98
How is TMV spread?
Through direct contact between diseased and healthy plant material, through soil and insects can act as vectors.
99
Name 2 bacterial diseases.
Salmonella
| Gonorrhoea
100
What are the early symptoms of gonorrhoea?
Has symptoms in the early stages but then becomes symptomless.
The early symptoms are a thick yellow/green discharge from the vagina or penis and pain on urination.
10% of infected men and 50% of infected women get no symptoms at all.
101
What happens if gonorrhoea is not treated?
Can cause long-term pelvic pain, infertility, and ectopic pregnancies.
Babies born to infected mother may have severe eye infections and even become blind.
102
Name a fungal diseases and a protist disease.
Rose black spot
| Malaria
103
How does your skin prevent you from pathogens?
Your skin acts as a barrier, and when you bleed, blood clots and scabs to prevent pathogens entering the body.
Your skin has antimicrobial secretions to destroy pathogenic bacteria.
Healthy skin is covered with microorganisms that keep you healthy and act as an extra barrier to the entry of pathogens.
104
Name 3 places in the body where there are defences for microorganisms.
The nose (full of hairs and mucus, traps particles)
The trachea and bronchi (secrete mucus to trap pathogens, and tube lining is covered in cilia that wafts the mucus up to the back of the throat where it's swallowed.
The stomach produces acid to destroy microorganisms in the mucus you swallow and pathogens in food taken through the mouth.
105
Name the 3 ways in which white blood cells protect the body from pathogens.
Ingesting microorganisms
Producing antibodies
Producing antitoxins
106
What is the purpose of a vaccine?
To stimulate you body's natural immune response to invading pathogens.
107
What is herd immunity?
If a large population is immune to a disease, the spread of the pathogen in the population is very much reduced, and the disease may even disappear.
108
How do antibiotics work?
They kill the bacteria that cause the disease while they are in the body, and damage bacterial cells without harming your own.
If you are very ill, antibiotics may be put straight in the bloodstream to make sure that they reach the pathogens in the cells as quick as possible.
109
Name 3 drugs from plants.
Digitalis
Digoxin
Aspirin
110
How did Alexander Flemming discover penicillin?
He was growing bacteria for study purposes, but he left the lift off his culture plates. He went on holiday, and came back to see clear rings around some sport of mould, showing that something had killed the bacteria. He called the 'something' penicillin, named after Penicillium mould which produced it.
111
List the order in which drugs are tested.
The drug is tested and grown in the laboratory.
The drug is tested on animals to study side effects.
The drug is tested on a small group of healthy human volunteers to check its safety.
The drug is tested on small numbers of volunteer patients to see if it works.
The drug is tested on large numbers of volunteer patients to monitor drug effectiveness, safety, dosage and side effects.
The drug is approved and can be prescribed.
112
Overall magnification formula
Eyepiece lens x objective lens
113
How do you measure the rate of photosynthesis for light intensity?
Set up apparatus (beaker with potassium carbonate) with test tube with pond weed, ruler, lamp.
Measure lengths
