B2.1.1 cell structure

Question 1

magnification

Answer 1

how many times larger an image is than the actual object itself

Question 2

resolution

Answer 2

the degree to which it is possible to distinguish between 2 objects that are very close together
(the higher the resolution, the greater detail you can see)

Question 3

total magnification equation

Answer 3

total magnification = eyepice lens magnification x objective lens magnification

Question 4

eyepiece lens magnification

Answer 4

always x10

Question 5

objective lens magnification

Answer 5

can be x4, x10, x40, x100

Question 6

staining

Answer 6

when coloured dyes bind to chemicals on/in the specimen so they’re more visible under a light microscope

Question 7

differential staining

Answer 7

staining with multiple dyes which allows different tissues to show up under a microscope

Question 8

sectioning

Answer 8

specimens are embedded in wax which is sliced very thinly without distorting the specimen structure
(useful for soft tissue e.g. brain)

Question 9

nucleus

Answer 9

structure:
- contains genetic information in the form of chromosomes
- surrounded by nuclear envelope (double membrane) containing pores
contains the nucleolus

function:
- controls the cell DNA contains instructions for producing proteins
- synthesis of ribosomes nucleolus makes ribosomal DNA
- exchange between nucleus and cytoplasm substances can enter/leace the nucleus via the nuclear pores

Question 10

cell surface membrane

Answer 10

structure:
- found on surface of animal cells
- mainly made up of lipids + proteins

function:
- controls movement of substances in/out of the cell membrane is partially permeable
- cell signalling has receptors that detect signals from other cells

Question 11

mitochondria

Answer 11

structure:
- surrounded by a double membrane
- inner membrane folds to form structures known as cristae
- inner part contains enzyme-rich fluid known as the matrix
- contains their own DNA + ribosomes
- 2-5μm

function:
- site of aerobic respiration produces ATP

Question 12

ribosomes

Answer 12

eukaryotic cells have 80S ribosomes
proaryotic cells have 70S ribosomes
structure:
- made up of proteins + rRNA (ribosomal RNA)
- some found free in cytoplasm or attached to rough endoplasmic reticulum (RER)

function:
- site of protein synthesis involved in translation

Question 13

golgi apparatus

Answer 13

structure:
- contains fluid-filled, membrane-bound sacs known as cisternae
- contains smaller vesicles

function:
- process and package lipids + proteins carried out by cisternae
- store and transport lipids + proteins carried out by vesicles