Cell Biology Flashcards
1
Q
Name all of the organelles in an animal cell
A
Nucleus, Ribosome, mitochondria, cytoplasm, cell membrane
2
Q
What is the role of:
1. The cytoplasm
2. The nucleus
3. The cell membrane
A
- The cytoplasm is the site of chemical reactions.
- The nucleus contains our genetic material.
- The cell membrane lets substances in and out of the cell.
3
Q
What is bigger - ribosomes or mitochondria?
A
Mitochondria
4
Q
Draw an animal cell and label the different organelles.
A
Correct diagram with all organelles labelled.
5
Q
State the function of:
1. The cell wall + what it’s made from.
2. The chloroplasts + what it’s filled with.
3. The vacuole + what is filled with.
A
- The cell wall: Strengthens the cell. It’s made from cellulose.
- The chloroplasts: Carry out photosynthesis. They are filled with chlorophyll.
- The vacuole: Keeps the cell turgid. It is filled with cell sap.
6
Q
Definitions of:
1. Eukaryotic cells
2. Prokaryotic cells
- Name 3 differences between them.
A
Eukaryotic cells: Their DNA is contained in a nucleus.
Prokaryotic cells: Their DNA is not contained in a nucleus.
- Eukaryotic cells are generally bigger than prokaryotic cells.
- Eukaryotic cells contain their DNA in a nucleus whereas prokaryotic cells do not.
- Eukaryotic cells have membrane bound organelles whereas prokaryotic cells do not.
7
Q
Give at least one example of a cell that falls into each category.
A
Eukaryotic: Animal and Plant
Prokaryotic: Bacterial cell
8
Q
How many meters is:
a) a mm
b) a micrometer
c) a nanometre
A
mm: x10 to the -3
micrometre: x10 to the -6
nanometre: x10 to the -9
9
Q
What is two orders of magnitude? What is 5 orders of magnitude?
A
2 orders of magnitude = 100x
5 orders of magnitude = 100,000x
10
Q
Write 1,000,000 in orders of magnitude.
A
6 orders of magnitude.
11
Q
Definition of diffusion.
A
The movement of particles from an area of high concentration to an area of low concentration.
12
Q
Explain how diffusion is used when oxygen goes into the cell.
A
- Cells are surrounded by a high concentration of oxygen.
- So oxygen diffuses from outside the cell to inside the cell (from an area of high concentration -> an area of low concentration.
13
Q
Explain how diffusion is used when carbon dioxide goes out of the cell.
A
- The mitochondria do aerobic respiration in the cell. A waste product of respiration is carbon dioxide.
- There is a high concentration of carbon dioxide in the cell, so it diffuses from an area of high concentration to an area of low concentration outside the cell.
14
Q
Explain how diffusion is used when urea goes out of the cell.
A
- Urea is a waste product produced inside the cells.
- It diffuses out of the cells from an area of high concentration to an area of low concentration in the blood plasma.
15
Q
What factors affect the rate of diffusion?
A
Surface area, Temperature and Concentration
16
Q
Explain how each of these 3 factors affect the rate of diffusion:
a) Surface area
b) Concentration + what is the concentration gradient?
c) temperature
A
- Surface area: The larger the surface area, the higher the rate of diffusion as there is more space for molecules to diffuse across the membrane.
- Concentration: The concentration gradient is the difference in concentration. The greater the concentration gradient, the faster diffusion takes place.
- Temperature: The higher the temperature, the faster diffusion takes place. This is because they have more kinetic energy and move faster causing more frequent collisions. This causes a quicker movement of substances across a membrane.
17
Q
Definition of osmosis.
A
The movement of water particles from an area of high water concentration to an area of low water concentration, through a semi permeable membrane.
18
Q
Definition of a semi permeable membrane
A
A membrane that allows some molecules to pass through, but not all of them.
19
Q
What will happen if we:
a) place an animal cell in water.
b) place an animal cell in a concentrated solution
A
a) The cytoplasm has a relatively low water concentration, so if we place the cell in water, then water will move by osmosis from outside to inside the cell. This will cause the cell to expand or even burst.
b) The cytoplasm has a relatively low water concentration, but if we place it in a very concentrated solution with less water molecules than the cell contains, the water inside the cell will move outside the cell by osmosis. This will cause the cell to shrink.
20
Q
Do concentrated or dilute solutions have more water molecules?
Does the cytoplasm have a high or low water concentration?
A
- Dilute solutions contain more water molecules than concentrated solutions.
- The cytoplasm has a relatively low water concentration.
21
Q
Definition of active transport
A
Active transport involves the movement of particles from a region of lower concentration to region of higher concentration, against the concentration gradient across a semi permeable membrane. The process requires energy.
22
Q
Give 2 differences between active transport and diffusion / osmosis
A
- Active transport moves against the concentration gradient whereas osmosis and diffusion both move along it.
- The process of active transport requires energy from respiration, whereas diffusion and osmosis don’t.
23
Q
What is chlorophyll + it’s role?
A
Chlorophyll is a green pigment that is light sensitive. It captures solar energy.
24
Q
- Write the word equation for anaerobic respiration in plants? In animals?
Where does anaerobic respiration take place in animals?
A
- Plants: glucose -> ethanol + carbon dioxide + energy
Animals: glucose -> lactic acid + energy. - The muscle cells.
25
Provide and explain an example of active transport in plants.
- Root hair cells need to transport mineral ions into plants such as magnesium.
- The concentration of mineral ions inside the cell is greater than outside the cell.
- Therefore mineral ions are moved into the cell by active transport. Then they are transferred into the Xylem.
26
Provide and explain an example of active transport in the body.
1. Molecules of digestive food are in the lumen of the small intestine. For example sugars
2. They need to diffuse into the cells, but they can’t as the cells have a higher concentration of glucose inside than in the lumen.
3. Instead, they move into the cells through active transport.
4. The cells also have lots of mitochondria to provide energy for active transport.
27
What is the definition of a stem cell?
A stem cell is an undifferentiated cells that can differentiate to form a different, specific type of cell.
28
What are embryonic stem cells?
Embryonic stem cells can differentiate to form cells. They can differentiate to form any type of cell.
29
Where else can you find stem cells? (other than an embryo)
What type of cells do these differentiate into?
1. Bone marrow
2. Platelets, RBCs or WBCs
30
Why do we do bone marrow transplants?
Explain the process of bone marrow transplants.
1. We do them to treat leukaemia.
2. Bone marrow transplant:
- a type of bone marrow cancer is leukaemia.
- to treat this, first the patients existing bone marrow is destroyed used radiation.
- the patient then receives a bone marrow transplant.
- the stem cells in the bone marrow then divide and form new bone marrow. They also differentiate to form blood cells.
31
Explain the process of therapeutic cloning
1. An embryo is produced with the same genes as the patient.
2. This means that stem cells from the embryos can be transported into the patient without being rejected by the patient’s immune system.
3. Once inside, the stem cells can differentiate to replace cells that stopped working.
32
Name 2 problems with therapeutic cloning.
1. It’s hard to find suitable stem cell donors.
2. It’s hard to store a patient’s embryonic stem cells.
33
Name 2 possible problems with bone marrow transplants.
1. The donor has to be compatible with the patient or the WBCs may attack the patients body.
2. There is a risk of viruses being passed from the donor to the patient.
34
Name 2 uses of stem cells
1. They can be used in bone marrow transplants to treat leukaemia.
2. They can regenerate and repair tissues that have been damaged or affected by disease.
35
Name 2 uses of meristem cells.
1. One use of a meristem cell is to clone a rare plant to stop it from going extinct.
2. Another use of a meristem cell is to produce cloned crops for farmers - like plants that’s resistant to disease.
36
Name 2 differences between adult stem cells and embryonic stem cells.
1. Embryonic cells can differentiate into any type of cells, whereas adult stem cells can differentiate into a limited number of cell types.
2. Embryonic stem cells are found in an embryo whereas adult stem cells are found in the body.
37
When are meristem tissues?
Meristem tissues are found in the tips of roots and shoots in plants. These plant tissues can differentiate into any type of plant tissue at any point.
38
Why do organisms need a high SA : V ratio?
- Because they rely on diffusion to transport oxygen and other substances in and out of the cell.
- Multicellular organisms get enough oxygen for the cells on the surface through diffusion, but not enough oxygen gets to the cells at the centre as they’re too far away from the surface.
39
Why have mammals developed lungs?
So that oxygenated blood can be transported and diffuse into every cell, instead of just the cells on the surface.
40
Describe the pathway that oxygen takes through the fishes respiratory system.
1. The oxygen rich water goes into their mouth, then the gills and is then transported to the bloodstream
2. The gills are covered in fine filaments, which is where gases pass in and out of the blood.
3. The deoxygenated blood goes into the filament. Oxygen diffuses from the water to the blood. The oxygenated blood then returns to the body.
41
Name 3 adaptations of filaments.
1. They have a thin membrane to provide a short capillary pathway.
2. The filaments give the gills a huge surface area.
3. The filaments have an efficient blood supply to take the oxygenated blood away.
42
What is the purpose of microscopes?
Name 2 disadvantages of light microscopes.
1. To magnify images and see things that we arent otherwise able to.
2. Limited magnification - up to 2000x
- limited resolution (blurry images)
43
Name 2 advantages of electron microscopes.
Name 2 disadvantages
Advantages:
- much better magnification than light microscopes.
- much better resolution than light microscopes.
Disadvantages:
- hard to store
- very expensive
44
How do you calculate magnification?
Image size / actual size = magnification
45
What is binary fission?
How often do bacteria do binary fission?
Name 2 factors bacteria need for optimal binary fission.
- one bacterial cell splits into 2 bacterial cells which we call binary fission.
- bacteria can carry out binary fission once every 20 minutes.
- a suitable temperature and pH.
46
How do you calculate the number of bacteria?
Number of bacteria = 2^n where
n = the number of rounds of bacterial division
47
Where are chromosomes found?
In the nucleus
48
Describe the three functions of mitosis takes place.
1. Mitosis is essential for the growth and development of multicellular organisms
2. Mitosis takes place when an organism repairs itself - eg broken bone heals
3. Mitosis happens during asexual reproduction
49
Calculate the number of bacterium present after 3 hours
3 hours = 180 minutes
180 / 20 = 9 rounds of division
2^9 512.
We divide 180 by 20 because bacteria reproduce every 20 minutes.
50
Why don’t bacteria multiply by mitosis?
Because there is no nucleus or chromosomes.
51
Describe the process of mitosis.
1. Mitosis begins with a parent cell containing 23 pairs of chromosomes .
2. The DNA replicates itself to form two copies of each chromosome. The cell now has 46 pairs of chromosomes.
3. The chromosomes line up across the centre of the cell.
4. One set of chromosomes is pulled to each end of the cell and the nucleus divides.
5. The cytoplasm and cell membranes divide to form 2 identical cells. These cells each have 23 pairs of chromosomes.
52
What are the jobs (2) of root hair cells?
The job of the root hair cell is to absorb water from the soil through osmosis.
They also absorb mineral ions through active transport.
53
Name 2 adaptations of root hair cells.
1. Root hair cells have root hair which increases the surface area of the root. This allows them to absorb water and dissolved mineral ions better.
2. They contain lots of mitochondria which provides them with energy for active transport.
54
What is the job of the xylem?
The xylem transports water and mineral ions from the roots to the rest of the plant.
55
Name 4 adaptations of the xylem
1. The xylem has very thick walls containing lignin. This gives the plant support.
2. The xylem is made up of dead cells.
3. The end walls of the xylem have broken down. This means water and mineral ions can flow quickly.
4. Xylem cells have no internal structures at all.
56
What is the job of the phloem?
The job of the phloem is to transport dissolved sugars up and down the plant.
57
Name 3 adaptations of the phloem.
1. The phloem has sieve plates on the end walls which help dissolved sugars to pass through.
2. Phloem cells are made up if 2 different types of cells - phloem vessel cells and companion cells.
3. The phloem vessel cells and companion cells are connected by pores.
58
What does differentiation mean?
Differentiation is the term used to describe animal cells becoming specialised.
59
What is the job of a sperm cell?
The job of a sperm cell is to fertilise an egg cell.
60
Name 3 adaptations of sperm cells.
1. Sperm cells have a long tail so help them swim to the egg cell.
2. Sperm cells have lots of mitochondria which provide them with the energy needed for swimming.
3. Sperm cells contain enzymes to help them digest the outer layer of the egg cell.
61
What is the job of a muscle cell?
The job of a muscle cell is to contract to allow for movement.
62
Name 3 adaptations of muscle cells
1. Muscle cells contain protein fibres which change their length.
2. The muscle fibres have lots of mitochondria which provide energy for muscle contraction.
3. Muscle cells work together to form muscle tissue.
63
What is the job of a nerve cell?
The job of a nerve cell is to send electrical impulses around the body.
64
Name 3 adaptations of nerve cells.
1. Nerve cells have dendrites which increase the surface area so that other cells can connect easier.
2. Nerve cells have a long axon which carries electrical impulses from one part if the body to another.
3. The end of the axon has synapses which are junctions that allow electrical impulses to pass from one nerve cell to another.
65
Why are the phloems companion cells so useful?
1. The phloem vessel cell has no nucleus and limited cytoplasm as the sugars need to get through. The companion cells which are attached to the phloem vessel cells have a nucleus, cytoplasm and mitochondria so that the phloem gets energy.
66
What are gametes?
Gametes are the female and male sex cells.
67
Name 3 adaptations of the egg cell
1. The egg cells cell membrane changes after fertilisation so that no more sperm can enter.
2. The nucleus contains 23 chromosomes- half of the genetic material.
3. The egg cells cytoplasm contains nutrients for the growth of the early embryo.
68
What is a zygote?
A zygote is a fertilised egg cell before it has developed into an embryo.
69
What is the difference in differentiation between animal and plant cells?
Most types of animal cells differentiate early in life, but plant cells retain the ability to differentiate throughout life.
70
How has electron microscopy increased understanding of sub cellular structures.
- Electron microscopes have a much higher resolution and magnification than light microscopes.
- this allowed scienetics to discover more sun cellular structures and work out their functions.
- through the use of electron microscopes, scientists were able to identify mitochondria which does aerobic respiration, and chloroplasts which do photosynthesis.
71
What are sub cellular structures?
They are structures that are found inside a cell - for example the nucleus .
72
Name 2 conditions treatment with stem cells may be able to help
Diabetes
Paralysis
