cells

Question 1

what are the distinguishing features of eukaryotic cells

Answer 1

cytoplasm containing membrane-bound organelles, so dna enclosed in a nucleus

Question 2

describe the structure of the nucleus

Answer 2

nuclear envelope
-double membrane
-has nuclear pores
nucleoplasm
nucleolus
-assembles ribosomes

Question 3

describe the function of the nucleus

Answer 3

-holds/stores genetic information which codes for polypeptides
-site of dna replication
-site of transcription
-nucleolus makes ribosomes/rRNA

Question 4

what are ribosomes made up of

Answer 4

rRNA and proteins

Question 5

describe the function of a ribosome

Answer 5

site of protein synthesis

Question 6

describe the structure of rough endoplasmic reticulum

Answer 6

folded membranes that contain ribosomes

Question 7

describe the function of rough endoplasmic reticulum

Answer 7

-ribosomes on surface which synthesise proteins
-proteins transported inside rER
-proteins packaged into vesicles for transport

Question 8

describe the structure of the golgi apparatus

Answer 8

flattened membrane sacs

Question 9

describe the structure of the golgi vesicle

Answer 9

small membrane sac

Question 10

describe the function of the golgi apparatus

Answer 10

-modifies proteins, e.g. adds carbohydrates to produce glycoproteins
-modifies lipids, e.g. adds carbohydrates to produce glycolipids
-packages proteins/lipids into golgi vesicles
-produces lysosomes

Question 11

describe the function of golgi vesicles

Answer 11

-forms vesicles to transport proteins/lipids to their required destination
-produces secretory enzymes
-forms lysosomes

Question 12

describe the structure of lysosomes

Answer 12

membrane bound organelle that releases hydrolytic enzymes

Question 13

describe the function of lysosomes

Answer 13

-release hydrolytic enzymes (lysosomes)
-to break down pathogens or worn out cell components

Question 14

describe the structure of mitochondria

Answer 14

-outer membrane
-cristae which is the inner membrane fold
-matrix, which contains small 70S ribosomes and circular DNA

Question 15

describe the function of the mitochondria

Answer 15

-site for aerobic respiration
-to produce ATP for energy release
-e.g. for protein synthesis, active transport

Question 16

describe the structure of the chloroplast in plants and algae

Answer 16

-double membrane
-stroma, containing thylakoid membranes, 70s ribosomes, circular DNA
-lamella, thylakoid linking grana
-grana, stacks of thylakoids (flattened sacs which increase the SA for respiration)

Question 17

describe the function of chloroplast in plants and algae

Answer 17

-absorb light energy for photosynthesis
-to produce organic substances e.g. carbohydrates/lipids

Question 18

describe the structure of the cell wall in plants, algae and fungi

Answer 18

plants/algae= composed mainly of cellulose
fungi= composed of chitin (a nitrogen containing polysaccharide)

Question 19

describe the function of the cell wall in plants, algae and fungi

Answer 19

-provides mechanical strength to cell
-so prevents cell changing shape or bursting under pressure due to osmosis

Question 20

describe the structure of the cell vacuole in plants

Answer 20

fluid filled sac with a single membrane
-contains cell sap

Question 21

describe the function of the cell vacuole in plants

Answer 21

-maintain turgor pressure in cell
-contains cell sap which stores sugars and amino acids

Question 22

describe how eukaryotic cells are organised in complex multicellular organisms

Answer 22

tissue-group of specialised cells with a similar story it working together to perform a specified function
organ-aggregations of tissues performing specific functions
organ system- group of organs working together to perform a specific function

Question 23

what are the distinguishing features of a prokaryotic cell

Answer 23

-cytoplasm lacking membrane bound organelles
-so genetic material not enclosed in a nucleus

Question 24

describe the structure of a prokaryotic cell that are always present

Answer 24

-cell surface membrane
-cell wall which contains murein
-cytoplasm
-small ribosomes
-circular dna, which is not associated with any proteins

Question 25

what are the features of prokaryotic cells that aren’t always present

Answer 25

-capsule
-plasmids, small rings of DNA
-flagella

Question 26

compare and contrasts the structure of eukaryotic and prokaryotic cells

Answer 26

EUKARYOTIC cell:
-has membrane bound organelles
-dna is long and linear and associated with histone proteins
-has a nucleus containing dna

PROKARYOTIC cell:
-no membrane bound organelles
-dna is short, circular, not associated with proteins
-no nucleus, dna is free in the cytoplasm

Question 27

explain why viruses are described as acellular and non-living

Answer 27

acellular- not made of cells, no cell membrane/cytoplasm/organelles
non living- having no metabolism, cannot independently move/respire

Question 28

describe the general structure of a virus particle

Answer 28

-nucleic acids surrounded by a capsid
-attachment proteins allow attachment to specific host cells
-no cytoplasm, ribsomes, cell wall etc
-some also surrounded by a lipid envelope e.g. HIV

Question 29

define magnification

Answer 29

how many times bigger an image viewed through a microscope is compared to the real object

Question 30

define resolution

Answer 30

the ability of a microscope to distinguish between 2 objects that are very close together

Question 31

formulae for magnification

Answer 31

M= image size/actual size