topic B1- cell biology

Question 1

what is an eukaryotic cell?

Answer 1

eukaryotic cells are complex and include all animal and plant cells

Question 2

what is a prokaryotic cell?

Answer 2

prokaryotes are a single celled organisms such as bacteria.

Question 3

what are all the properties of an animal cell?

Answer 3

nucleus- contains genetic material, controlling the activities of the cell.
mitochondria- most aerobic respiration takes place, transferring energy that the cell needs to work.
cytoplasm- gel-like substance where most of the chemical reactions happen, it contains enzymes.
cell membrane- holds the cell together and controls what goes in and out.
ribosomes- these are where proteins are made.

Question 4

what are the properties of a plant cell?

Answer 4

has everything a plant cell has including some additional things:
rigid cell wall- made of cellulose (supports the cell and strengthens it)
chloroplasts- where photosynthesis occurs, making food for the plant (include chlorophyll, which absorbs light needed for photosynthesis)

Question 5

what are the properties of a bacterial cell?

Answer 5

don’t have a true nucleus- have a singular strand of DNA, floats freely in the cytoplasm.
plasmids- one or more small rings of DNA
contain cell membrane, cell wall

Question 6

what is the purpose of light microscopes?

Answer 6

uses light and lenses to form images and magnify it. Can show individual cells and large subcellular structures (nuclei)

Question 7

what is the purpose for electron microscopes

Answer 7

use electrons to form an image, have a higher resolution. see much smaller things in detail, like the internal structure of mitochondria and chloroplasts, can also help to see tinier things such as ribosomes and plasmids.

Question 8

what is the equation for magnification?

Answer 8

image size divided by real size.

Question 9

how do you prepare a slide?

Answer 9

1) Add a drop of water to the middle of a clean slide.
2) Cut an onion and separate into layers, use tweezers to pull off some epidermis tissue from the bottom.
3) Using tweezers, place the epidermal tissue into the water on the slide.
4) Add a drop of iodine solution, stains are used to highlight objects, making them easier to see.
5) place a cover slip on the tissue, carefully lower it so it covers specimen, take time since any air bubbles will obstruct your view.

Question 10

how do you use a light microscope to look at your slide?

Answer 10

1) clip the slide you have prepared onto the stage
2) select the lowest-power objective lens (produces lowest magnification)
3) use the course adjustment knob, to move the stage up to just below the objective lens.
4) look down the eyepiece. use the coarse adjustment knob, until you get a clear image of what’s on the slide.
5) adjust the focus with the fine adjustment knob, until you get a clear image of what’s on the other side.

Question 11

what is cell differentiation

Answer 11

differentiation is the process by which a cell changes to become specialised for its job.

Question 12

how is a sperm cell specialised for it reproduction?

Answer 12

1) long tail and streamlined head to help it swim to the egg.
2) there is lots of mitochondria in the cell to provide it with energy needed.
3) it has enzymes in its head to digest through the the egg cell membrane.

Question 13

how is a nerve cell specialised for rapid signalling?

Answer 13

1) they are long to cover more distance
2) branched connections at the ends to connect to other nerve cells and form a network in the body.

Question 14

how is a muscle cell specialised for contraction?

Answer 14

1) they are long so they have space to contract
2) contain lots of mitochondria to generate energy needed for contraction.

Question 15

how is a root hair specialised for absorbing water and minerals?

Answer 15

gives the plant a large surface area for absorbing water and mineral ions from the soil.

Question 16

how are phloem and xylem cells specialised for transporting substances?

Answer 16

1) the cells are long and joined end to end.
2) xylem cells are hollow in the centre and phloem cells have very few subcellular structures so that stuff can flow through them.

Question 17

what happens if a cell doesn’t differentiate?

Answer 17

they turn into stem cells, which can divide to produce lots more undifferentiated cells.

Question 18

where can stem cells be found?

Answer 18

1) hey are found in early human embryos, they can turn into any kind of cell.
2) adults also have stem cells but they are only found in certain places such as bone marrow, they cannot turn into any kind of cell.

Question 19

how can adult stem cells be used to cure disease?

Answer 19

stem cells can be transferred from a healthy persons bone marrow to replace faulty blood cells in a sick person

Question 20

how can embryonic stem cells be used to replace faulty cells?

Answer 20

you could make insulin producing cells for people with diabetes or nerve cells for people paralysed with spinal injuries.

Question 21

what is therapeutic cloning?

Answer 21

where an embryo is made to have the same genetic information as the patient. this way they wouldn’t be rejected by the patients cells.

Question 22

what are the risks of using stem cells in medicine?

Answer 22

they become become contaminated with a virus and make the person even sicker.

Question 23

what are some of the ethical issues of stem cell research?

Answer 23

1) human embryos shouldn’t be used for experiments since each one is a potential life.
2) others believe that curing existing patients is more important than the rights of embryos.
3) embryos used in research are unwanted ones from fertility clinics which would be destroyed anyway
4) in some countries stem cell research is banned (its allowed in the UK as long as it follows strict guidelines)

Question 24

what is a chromosome?

Answer 24

a coiled up length of DNA

Question 25

what is the cell cycle?

Answer 25

body cells in multicellular organisms divide to produce new cells as part of a series of stages.