Topic B1 - Cell Biology

Question 1

Nucleus

Answer 1

Contains genetic material that controls activity of cell

Question 2

Eukaryotic cells

Answer 2

Animal and plants cells

Question 3

Prokaryotic cells

Answer 3

Bacteria

Question 4

Cytoplasm

Answer 4

Gel-like substance where most of the chemical reactions happen. It contains enzymes that control these chemical reactions

Question 5

Cell membrane

Answer 5

Hold cell together and controls what goes in and out

Question 6

Mitochondria

Answer 6

These are where most of the reactions for aerobic respiration take place. Respiration transfers energy that the cell needs to work

Question 7

Riobosomes

Answer 7

Where proteins are made in the cell

Question 8

Rigid cell wall (plant cell)

Answer 8

Made of cellulose. It supports the cell and strengthens it

Question 9

Permanent vacuole (plant cell)

Answer 9

Contains cell sap. A weak solution of sugar and salts

Question 10

Chloroplasts

Answer 10

Where photosyntheis oocurs, which makes food for the plant. Contains chrlophyll which absorbs light needed for photosynthesis

Question 11

Bacteria cells

Answer 11

Cell membrane, cell wall, ribosomes and cytoplasm. They have a singular strand of DNA that floats freely in the cytoplasm

Question 12

Light microscope

Answer 12

Arm, base, light source, stage, microscope slide, objective lense, body tube, coarse focusing knob, fine focusing knob, eyepiece lense

Question 13

Magnification formula

Answer 13

Magnifictaion=image size/real size

Question 14

Electron microscope

Answer 14

Higher detail than light microscope

Question 15

Magnificaton

Answer 15

How many times larger the image is than the object

Question 16

Resolution

Answer 16

A measure of how detailed an image is

Question 17

Pros of light microscopes

Answer 17

Easy to use, relatively cheap however low resolution

Question 18

Pros and cons Electron microscopes

Answer 18

Very expensive, hard to use, high resolution

Question 19

How to prepare slide

Answer 19

Add drop of water onto slide, use tweezers to peel off epidermal tissue and place on the water on the slide, add of drop of iondine to stain, place over cover slip

Question 20

How to use light microscope

Answer 20

Clip slide onto stage, select lowest objective lens, use coarse adjustment lens to move stage up just below lens, look down the eyepeice and use coarse adjustment to get a rought image, adjust focus with fine knob

Question 21

Units of convertion

Answer 21

Nanometres, micrometres, minimetres, metres, kilometres (x1000 for each one)

Question 22

Chromosomes

Answer 22

Coiled up lengths of dna molecules, 23 in human boh

Question 23

Cell cycle

Answer 23

Growth, dna replication and mitosis

Question 24

Growth and DNA replication

Answer 24

In a cell thats not dividing the DNA is spread out into long strings, the cell has to grow and increases the amount of subcellular structures, it then duplicates its DN

Question 25

Mitosis

Answer 25

Once the cells contents and DNA have been copied the chromosome line ip st the centre of the cell and cell fibres pull them apart . The teo arms of the chromosome go to opposite ends of the cell. The membrane form sround each of the sets of chrmosomes. These come bcdom the nuclei of the two new cells- the nucelus divides, lastly the cytoplasm and cell membrane divide

Question 26

2 key features of stem cells

Answer 26

Can divide by mitosis to form more cells, able to differentiate into specialised cells

Question 27

Differentiation

Answer 27

Process by which a cell changes to become specialised for its job

Question 28

Where are stem cells founds

Answer 28

Early human embryos or bone marrow but unlike embryonic stems cells they can't turn into any type of cell

Question 29

Why are stem cells helpful

Answer 29

Can replace faulty cells and wont be rejcted by body as has sams genetic information

Question 30

Why are some people against stem cell research

Answer 30

They feel that human embryos shoudlnt be used since esch each od potential human life

Question 31

Stems cells in plants

Answer 31

Found in meristems, can differentiate into and type of plant

Question 32

Uses of stem cells in plants

Answer 32

Stem cells can be used to produce clones of whole planys quickly and cheaply, grow more planys of rare species, ccan be used to grow cropd of identical planys with desired features such as disease resistance

Question 33

Sperm cell - reproduction

Answer 33

Get male DNA to Female DNA. Adaptations- long tail and streamlined head, lots of mitochondria to provide energy needed, carries enzymes in its head to digesy through the egg cell membrane

Question 34

Nerve cells- rapid signalling

Answer 34

Carry electrical signals from one part of the body to anotjer. Adaptations- long (cover more distance) and have branched connectiond st their ends to connecy to other nerve cells to form a network throughout the body

Question 35

Muscle cells- contraction

Answer 35

Function is to contravt quickly. Adaptations- they are long ( so have more space to contract) and contain lots of mitochondria to generate the energu needed for contraction

Question 36

Root hair cells- absorbing water and minerals

Answer 36

Root hair cells are cells on the surgavd of plant roots which gros into long hairs and stick out on the soil and gives the plant big surface area for absorbing water and mineral ioms