B1 Flashcards
(88 cards)
1
Q
What is a eukaryotic cell?
A
- Large compared to prokaryotic cells.
- Has a nucleus
- Human body cells are a type of eukaryotic cells.
2
Q
What is a prokaryotic cell?
A
- Smaller compared to eukaryotic cells.
- Do not have a nucleus.
- Bacteria cells are a type of prokaryotic cells.
3
Q
What is the function of the nucleus?
A
- Contains genetic information.
- Controls the activities of the cell.
4
Q
What is the function of the cell membrane?
A
Controls what goes in and out of the cell.
5
Q
What is the function of the cytoplasm?
A
Most chemical reactions occur here.
6
Q
What is the function of the mitochondria?
A
To release energy through the process of respiration.
7
Q
What is the function of the ribosomes?
A
Protein synthesis.
8
Q
What is diffusion?
A
Particles moving from an area of high concentration to an area of low concentration.
9
Q
What is osmosis?
A
Water molecules moving from an area of high concentration to an area of low concentration through a partially permeable membrane.
10
Q
What is active transport?
A
Particles moving from an area of low concentration to an area of high concentration. This process requires energy from respiration that occurs in the mitochondria.
11
Q
What is the difference between an animal cell and a plant cell?
A
A plant cell has a cell wall, a vacuole and chloroplast.
12
Q
What is the function of the cell wall?
A
Supports the cell.
13
Q
What is the function of the vacuole?
A
Keeps the cell turgid.
14
Q
What is the function of the chloroplast?
A
- Contain chlorophyll.
- Converts energy from the sun into food.
15
Q
What does a bacterial cell have?
A
- Cell membrane.
- Cell wall.
- Cytoplasm.
- Ribosomes.
- Single strand of DNA.
- Plasmids
- Flagella
16
Q
What is the function of plasmids?
A
Contain genetic information.
17
Q
What is the function of the flagella?
A
To help the bacteria cell move.
18
Q
Define magnification.
A
How zoomed in the image is.
19
Q
Define resolution.
A
How clear the image is.
20
Q
Name 2 types of microscopes.
A
- Light microscope.
- Electron microscope.
21
Q
Why is the electron microscope better?
A
- Higher magnification.
- Higher resolution.
22
Q
What is the magnification equation?
A
Image / Actual = Magnification.
23
Q
How do you convert millimetres to micrometers?
A
X 1,000.
24
Q
What does the coarse focusing wheel do?
A
Roughly focuses the image by moving the stage up and down.
25
What does the fine focusing wheel do?
Makes the cells sharp and clear.
26
What do the objective lens do?
Change the magnification of the image.
27
What is a specialised cell?
They have adaptations or a specific structure that allows them to do their particular function more efficiently.
28
What is the function of the sperm cell?
To swim to the egg and fertilise it.
29
What does the sperm cell have?
- Nucleus.
- Mitochondria.
- Enzymes.
- Tail.
30
How does lots of mitochondria help the sperm cell?
Respiration occurs in the mitochondria and generates lots of energy, allowing the sperm cell to swim to the egg.
31
How do the enzymes help the sperm cell?
Help breakdown the membrane of the egg.
32
How does the tail help the sperm cell?
Helps it swim to the egg.
33
What does a yeast cell contain?
- Chitin cell wall.
- Cell membrane.
- Cytoplasm.
- Nucleus.
- Mitochondria.
- Ribosomes.
- Vacuole.
34
How do you calculate total magnification?
Eyepiece Magnification (x5 or x10)
x
Objective Lens Magnification (x4, x10, x40)
35
What is the function of a nerve cell?
To send electrical impulses around the body.
36
What is the function of dendrites?
Gives the nerve cell a large surface area to connect to other cells.
37
What is the function of a long axon?
Carries signals long distances around the body.
38
What are the function of the myelin sheets?
Insulates axons so electrical signals are not lost.
39
What are synapses?
Gaps between the cells.
40
What is the function of muscle cells?
To contract and form movement.
41
What is the function of having lots of mitochondria in muscle cells?
Energy.
42
What is the function of protein fibres in muscle cells?
Change sizes to help muscles to contract.
43
What is the function of root hair cells?
Increase the surface area of the roots so it can absorb water and dissolved minerals more effectively.
44
How does the big vacuole help the root hair cell?
Keeps it turgid.
45
Why don’t root hair cells contain chloroplasts?
The roots are underground so no sunlight will reach them.
46
Where is the xylem cell found?
In the meristem.
47
What is the function of xylem cells?
They carry water and dissolved minerals from the roots to the leaves through the stem.
48
What do the thick walls contain and how do they help the xylem cell?
- Lignin.
- It supports the cell.
49
How does the xylem cell being hollow help it?
Makes it easier for water and dissolved minerals to flow.
50
What is the function of the phloem cell?
Carry dissolved sugars up and down the stem.
51
What is special about the phloem vessel cells?
- Do not contain a nucleus.
- Only limited by cytoplasm.
52
What is the function of sieve plates?
Allow dissolved sugars to move through the cell interior.
53
When can animal cells differentiate?
At a young age. As they develop, they lose the ability.
54
When can plant cells differentiate?
Throughout it’s life.
55
What is cell division mainly restricted to in mature animals?
- Repair cells.
- Replace cells.
56
How many chromosomes are there in a body cell?
46.
57
How many chromosomes are there in sex cells and why?
23. This is because it fuses with the another sex cell to form 46 chromosomes.
58
What is a haploid cell?
23 chromosomes.
59
What is a diploid cell?
46 chromosomes.
60
Why is cell division by mitosis important?
To replace and repair.
61
What happens in stage 1 of mitosis?
- Cell increases in size.
- DNA replicates itself.
- Increase in organelles e.g. mitochondria and ribosomes.
62
What is stage 2 of mitosis and called what happens?
- Stage 2 is called mitosis.
- Chromosomes line up in the middle.
- They are then pulled to each end by fibres.
- The nucleus divides.
63
What happens in stage 3 of mitosis?
- Cell membrane divides.
- Cytoplasm divides.
- You are left with two genetically identical cells.
64
What is a stem cell?
An unspecialised cell that can differentiate into a specialised cell.
65
What are the three types of stem cells?
- Embryonic stem cells.
- Adult stem cells.
- Plant stem cells.
66
Where are plant stem cells located?
In the meristem.
67
What is the function of embryonic stem cells?
Can specialise into any cell.
68
What is the function of adult stem cells?
Can specialise into blood cells: red blood cells, white blood cells and platelets.
69
What is the function of plant stem cell?
Can differentiate into any plant cell during the plant’s cell.
70
What two conditions do stem cells help with?
- Paralysis.
- Diabetes.
71
What is therapeutic cloning?
Making an embryo with the same genes as the patient so the body won’t reject it.
72
What are the advantages of therapeutic cloning?
- Reduced waiting time for organ transplants.
- Cure medical conditions.
- Can be used for research.
- Many cells are produced.
- Cells are unlikely to be rejected by the patient.
- Cells/tissues of any type can be produced.
73
What are the disadvantages of therapeutic cloning?
- Potential life is killed.
- Shortage of donors.
- Egg donation/collection has risks.
- Do not yet know the risks/side effects of the procedure.
- Poor success rate to produce viable eggs/embryo.
- May transfer viral infections.
74
What are the advantages of using stem cells from plants?
- Clone rare species of plants to stop them from becoming extinct.
- Farmers can clone crops to sell quickly and cheaply.
75
How are surfaces adapted for efficient gas exchange?
- Good blood supply which maintains high concentration gradient.
- Large surface area.
- Thin walls for short diffusion pathway.
76
How does gas exchange happen in the lungs?
- There is a high concentration of O2 in the alveoli.
- There is a low concentration of O2 in the red blood cell.
- O2 diffuses from the alveoli to the red blood cells.
- There is a high concentration of CO2 in the red blood cells.
- There is a low concentration of CO2 in the alveoli.
- CO2 diffuses from the red blood cells to the alveoli.
77
What are the adaptations of gas exchange in the lungs?
- Large surface area for faster rate of diffusion.
- Moist lining for dissolving gases.
- Thin walls for a short diffusion pathway.
- Good blood supply to maintain a high concentration gradient.
78
What is the function of the small intestine?
Where nutrients from the food are absorbed into the bloodstream.
79
What are the adaptations of the small intestine?
- Lots of villi. These villi have microvilli. These greatly increase the surface area so food is absorbed more quickly into the blood.
- One cell thick for a short diffusion pathway.
- Good blood supply to maintain a high concentration gradient.
80
How does carbon dioxide diffuse into plants?
Diffuses into the air spaces within the leaf, then it diffuses into the cells where photosynthesis occurs.
81
What are the adaptations of plant cells (exchanging substances)?
- The underneath of the leaf is covered in holes called stomata.
- The stomata is controlled by guard cells. They close if the plant is losing water faster than it is being replaced by the roots.
- Flat shape increases the area of the exchange surface so it’s more effective.
82
How does oxygen get into the fish?
- Water contains oxygen.
- Water enters the fish through its mouth and passes out through its gills.
- Oxygen diffuses from the water into the blood in the gills.
- Carbon dioxide diffuses from the blood into the water.
83
How are the gills in a fish adapted?
- Gill filaments increase the surface area.
- Gill filaments have lamella which furhrrr increase the surface area.
- Lamellae have lots of blood capillaries to speed up the rate of diffusion.
- Thin surface layer for a short diffusion pathway.
- Blood flows through the lamella in direction and water flows in the opposite direction to maintain a high concentration gradient.
84
What is a partially permeable membrane?
Allows some substances to pass through.
85
How does active transport happen in the root hair cell?
- There is a high concentration of minerals in the root hair cell.
- There is a low concentration of minerals in the soil.
- Minerals move from a low concentration to a high concentration (soil to root hair cell) by active transport.
86
How many types of cells are there?
2:
1. Eukaryotic cells.
2. Prokaryotic cells.
87
What is the point of the microscope experiment?
- To prepare a slide to view under the microscope.
- To set up and use a microscope.
88
What is the method to prepare an onion slide?
1. Use a dropping pipette to put one drop of water onto a microscope slide.
2. Separate one of the thin layers of the onion.
3. Peel off a thin layer of epidermal tissue from the inner surface.
4. Use forceps to put this thin layer on to the drop of water that you have placed on the microscope slide.
5. Make sure that the layer of onion cells is flat on the slide.
6. Put two drops of iodine solution onto the onion tissue.
7. Carefully lower a coverslip onto the slide.
8. Put the slide on the microscope stage.
