Biology Topic 1 - Cell Biology

?
What kind of cells have a nucleus?
Eukaryotes. Prokaryotes are single celled organisms.
1 of 54
Nucleus
Contains genetic material that controls the cell.
2 of 54
Cytoplasm
This is where chemical reactions happen- it contains enzymes.
3 of 54
Cell Membrane
Holds the cell together and controls what goes in and out.
4 of 54
Mitochondria
Aerobic respiration happens here to release energy.
5 of 54
Ribosomes
Where proteins are made (protein synthesis).
6 of 54
Cell Wall
Made of cellulose- supports and strengthens the cell.
7 of 54
Permanent Vacuole
Contains cell sap, a weak solution of sugar and salts.
8 of 54
Chloroplasts
Where photosynthesis occurs, making food for the plant (contains chlorophyll to absorb light)
9 of 54
What three parts does a plant cell have that animal cells don't?
Cell Wall, Vacuole, Chloroplasts
10 of 54
Describe the structure of a bacterial cell.
They're much smaller, with a cell membrane, cell wall and cytoplasm. They don't have chloroplasts mitochondria, or a true nucleus- they have a single circular strand of DNA that floats freely instead. They may also contains one or more plasmids.
11 of 54
What does a light microscope do?
They use light and lenses to form an image and magnify it. They let us see individual cells and large sub cellular structures, such as nuclei
12 of 54
What do electron microscopes do?
They use electrons instead of light to form an image, and have a much higher magnification and resolution, giving us a sharper image and allowing us to see mitochondria, chloroplasts, ribosomes and plasmids.
13 of 54
What is the formula for magnification?
Magnification = image size/real size
14 of 54
What is cell differentiation?
This is when cells differentiate to become specialised, allowing them to carry out a specific function.
15 of 54
Describe a sperm cell (reproduction).
The function of a sperm is to take male DNA to female DNA. It has a long tail and streamlined head to help it swim to the egg, a lot of mitochondria to provide the energy needed and enzymes in the head to help it digest through the egg cell membrane.
16 of 54
Describe a nerve cell (rapid signalling).
The function of a nerve cell is to carry electric signals to parts of the body. They are long to cover more distance and have branched connections (dendrites) to connect to other nerve cells and form a network.
17 of 54
Descrive a muscle cell (contraction).
The function of a muscle cell is to contract quickly. They are long so they have space to contract and contains lots of mitochondria to release the energy needed.
18 of 54
Describe a root hair cell (absorbing water and minerals).
Root hair cells are on the surface of plant roots, which grow into long 'hairs' that stick out into the soil. This gives the plant a big surface area for absorbing water and mineral ions.
19 of 54
Describe xylem and phloem (transporting substances).
Phloem and xylem cells form phloem and xylem tubes, which transport food and water around plants. The cells are long and joined end to end to form tubes. Xylem cells are hollow in the centre and phloem cells have very few sub cellular structures.
20 of 54
What are chromosomes?
They are coiled up lengths of DNA molecules, carrying a large number of genes. Different genes control the development of different characteristics.
21 of 54
How many pairs of chromosomes does a human cell have?
23
22 of 54
What is the purpose of mitosis?
Mitosis is used to grow or replace cells that have been damaged (growth and repair). The end of the cycle results in two new cells identical to the original cell, with the same number of chromosomes.
23 of 54
What happens during mitosis?
The cell duplicates its DNA, and forms X-shaped chromosomes. The chromosomes line up in the centre and cell fibres pull them apart.
24 of 54
What happens during binary fission?
The DNA replicates and the strands move to opposite poles of the cell. The cytoplasm divides and two daughter cells are produced- they have one copy of the circular DNA but can have a variable number of plasmids.
25 of 54
Where are bacteria (and some other microorganisms) cultured and why?
They are cultured in a 'culture medium' which contains the carbohydrates, minerals, proteins and vitamins they need to grow. This culture medium could be a nutrient broth solution or a solid agar jelly.
26 of 54
What happens to bacteria grown on agar plates?
They will spread out and form visible colonies.
27 of 54
How do you make an agar plate?
Hot agar jelly is poured into Petri dishes, and when the jelly cools it sets. Then, inoculating loops or a pipette and a spreader can be used to transfer microorganisms.
28 of 54
What is the difference between the temperatures used in a lab at school and in industrial conditions?
In a lab, the temperature is 25 degrees or below because harmful pathogens can grow above this temperature. In industrial conditions, cultures are incubated at higher temperatures to get faster results.
29 of 54
What aseptic techniques should be used?
Light a Bunsen burner to kill bacteria in the air, sterilise the inoculating loop by wafting it through a flame, sterilise the petri dishes to kill unwanted microorganisms and disinfect the surfaces before use.
30 of 54
How should Petri dishes be stored?
Tape them at four points to stop microorganisms from the air getting in. They should not be taped all the way around as this can lead to the growth of dangerous anaerobic bacteria. Store the Petri dish upside down to prevent condensation falling.
31 of 54
What are stem cells?
Stem cells are unspecialised cells that can differentiate into specialised cells.
32 of 54
Where are stem cells found?
Stem cells can be found in early human embryos (can turn into any kind of cell) and in adult bone marrow (limited differentiation).
33 of 54
What can stem cells be used for?
Adult stem cells= cure disease (e.g replace faulty blood cells) Embryonic stem cells= replace faulty cells (eg. nerve cells/insulin producing cells), therapeutic cloning (stem cells have the same genes as patient so won't be rejected).
34 of 54
What is the risk of using stem cells?
Stem cells grown in the lab may become contaminated with a virus which could be passed on to the patient and make them sicker.
35 of 54
Why are some people against stem cell research?
Some people believe that human embryos shouldn't be used for experiments because each one is a potential human life. Scientists should concentrate on other sources of stem cells, and in some countries this research is banned.
36 of 54
What are the arguments in favour of using stem cells?
Some people believe that curing existing patients who are suffering is more important than embryo rights. Embryos are usually unwanted ones from fertility clinics which would otherwise be destroyed.
37 of 54
Where are stem cells found in a plant and what can they be used for?
Stem cells are found in the meristems (tip of the plant where growth occurs). These cells can be used to produce clones, grow more plants or rare species, and grow crops of identical plants with desired features (such as disease resistance).
38 of 54
What is diffusion?
The spreading out of particles from a high to a low concentration.
39 of 54
How can diffusion be sped up?
Increase concentration gradient, increase temperature, increase surface area and decrease diffusion path.
40 of 54
Dissolved substances can move in and out of the cell by diffusion. What kind of molecules can diffuse through cell membranes?
Very small molecules (such as oxygen, glucose, amino acids and water) can diffuse through cell membranes, but big molecules (e.g starch, proteins, carbohydrates) cannot.
41 of 54
What is osmosis?
The movement of water molecules from a high water concentration to a low water concentration across a partially permeable membrane.
42 of 54
What is active transport?
Active transport is where substances are absorbed against the concentration gradient.
43 of 54
Where does active transport take place in plants and why?
Active transport takes place in the root hair cells because the concentration of minerals is usually higher in the root hair cells than it is in the soil around them.
44 of 54
Where does active transport take place in humans and why?
Active transport is used in the gut when there is a lower concentration of nutrients in the gut, but a higher concentration of nutrients in the blood.
45 of 54
What does active transport require?
Energy from respiration.
46 of 54
How are exchange surfaces adapted?
Exchange surfaces have to allow enough of the necessary substances to pass through, They have a thing membrane, a large surface area, lots of blood vessels and in the case of gas exchange are often ventilated.
47 of 54
The job of the lungs is to transfer oxygen to the blood and remove waste carbon dioxide from it. How are the lungs adapted for this?
They contain millions of little air sacs called alveoli. They have an enormous surface area, a moist lining, very thin walls and a good blood supply.
48 of 54
How is the small intestine adapted for digested food to be absorbed quickly into the blood?
The inside of the small intestine is covered in millions of villi, which increase the surface area, have a single layer or surface cells and a very good blood supply.
49 of 54
What are stomata and what do they do?
The underside of the leaf is covered in lots of small holes called stomata. This is where carbon dioxide diffuses in, and oxygen and water vapour diffuse out. Guard cells close the stomata if the plant is losing water faster than it is being replaced
50 of 54
How else are leaves adapted for diffusion?
The flattened shape of the leaf increases the surface area, and the air spaces inside the leaf increase the area of the cell walls.
51 of 54
What gases are exchanged in a fish?
Water (containing oxygen) enters the fish through its mouth and passes out through the gills. Oxygen then diffuses from the water into the blood, and carbon dioxide diffuses from the blood into the water.
52 of 54
How are the gills adapted to have a large surface area?
Each gill is made of lots of thin plates called gill filaments, which increase the surface area. The gill filaments are covered in lamellae, which increase the surface area even more.
53 of 54
How are the lamellae adapted to speed up diffusion?
They have lots of blood capillaries, a thin surface layer of cells and a large concentration gradient between the water and the blood (flowing in opposite directions)
54 of 54

Other cards in this set

Card 2

Front

Nucleus

Back

Contains genetic material that controls the cell.

Card 3

Front

Cytoplasm

Back

Preview of the front of card 3

Card 4

Front

Cell Membrane

Back

Preview of the front of card 4

Card 5

Front

Mitochondria

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Cells, tissues and organs resources »