3.2 Cells

Question 1

What are all the sub cellular structures in a eukaryotic cell?

Answer 1

Nucleus
Mitochondria
Ribosomes
Golgi apparatus
Endoplasmic reticulum
lysosomes
Centrioles

Question 2

What extra sub cellular structures do plant cells have?

Answer 2

Permanent Vacuole
Chloroplast
Cell wall

Question 3

what is the cell-surface membrane?

Answer 3

it regulates the movement of substances into and out of the cell. it has receptor molecules which allow it to respond to chemicals like hormones

Question 4

describe the structure of the nucleus?

Answer 4

the nucleus is surrounded by a nucleur envelope (double membrane) which contains nucleur pores. the nucleus contains chromosomes and a nucleolus

Question 5

describe how the nucleus controls cell activity

Answer 5

by controlling the transcription of DNA, the DNA contains instructions to make proteins

Question 6

what is the function of the nuclear pores in the nucleus?

Answer 6

the nucleur pores allow substances to move between the nucleus and the cytoplasm

Question 7

what does the nucleolus produce?

Answer 7

ribosomes

Question 8

what is the structure of the mitochondria?

Answer 8

they have a double membrane, the inner one is folded to form structures called cristae which contains the matrix

Question 9

what does the matrix contain?

Answer 9

enzymes for respiration

Question 10

where does aerobic respiration occur?

Answer 10

within the mitochondria

Question 11

what does aerobic respiration produce?

Answer 11

ATP

Question 12

where are chloroplasts found?

Answer 12

in the plant cells and algal cells

Question 13

describe the structure of chloroplasts

Answer 13

they are surrounded by a double membrane and contain thylakoid membranes which are stacked up to form grana, grana are linked together by lamellae

Question 14

what are thylakoid membranes?

Answer 14

membranes inside the cell

Question 15

what are lamellae?

Answer 15

thin flat pieces of thylakoid membrane

Question 16

where does photosynthesis occur?

Answer 16

in the chloroplasts

Question 17

what form grana?

Answer 17

stacked up thylakoid membranes

Question 18

what link grana together?

Answer 18

lamellae

Question 19

what are the 2 stages of photosynthesis?

Answer 19

light dependent stage
light independent stage

Question 20

where does the light dependant stage take place?

Answer 20

in the thylakoids as that is where chlorophyll is present

Question 21

where does the light independent stage take place?

Answer 21

in the stroma

Question 22

what is the stroma?

Answer 22

thick fluid found in chloroplasts

Question 23

what is a Golgi apparatus?

Answer 23

a group of fluid filled, membrane bound sacs

Question 24

what is the function of the Golgi apparatus?

Answer 24

they modify and package proteins and lipids into Golgi vesicles, they also make lysosomes

Question 25

where is the Golgi vesicles found?

Answer 25

in the cytoplasm

Question 26

where are Golgi vesicles produced?

Answer 26

golgi apparatus

Question 27

what is the function of the Golgi vesicles?

Answer 27

to store proteins and lipids produced in the Golgi apparatus and transports them out of the cell to the required destination via the cell surface membrane

Question 28

what do lysosomes contain?

Answer 28

hydrolytic enzymes called lysozymes

Question 29

what do lysozyme enzymes do?

Answer 29

they break down biological molecules, damaged organelles, and pathogens

Question 30

what are lysosomes?

Answer 30

membrane bound organelles

Question 31

what is the structure of ribosomes?

Answer 31

they are formed form a small sub unit and a large sub unit

Question 32

where does protein synthesis take place?

Answer 32

ribosomes

Question 33

what is the structure of the rough endoplasmic reticulum?

Answer 33

its surface is covered in ribosomes

Question 34

what is the function of the rough endoplasmic reticulum?

Answer 34

folds and processes proteins produced by the ribosomes

Question 35

what is the function of the smooth endoplasmic reticulum?

Answer 35

to process, store and transport lipids and carbohydrates

Question 36

what is the function of the cell wall?

Answer 36

to support the cell and prevent shape change

Question 37

what is the cell wall made of in algae and plants?

Answer 37

cellulose

Question 38

what is the cell wall made of in fungi?

Answer 38

chitin

Question 39

where is the cell vacuole found and what does it contain?

Answer 39

cytoplasm in a plant cell it contains cell sap

Question 40

what is the surrounding membrane of the vacuole called?

Answer 40

tonoplast

Question 41

what is the function of the vacuole?

Answer 41

maintains pressure inside cell and keeps the cell rigid

Question 42

what are specialised cells organised into?

Answer 42

tissues->organs->organ system

Question 43

what are the differences between prokaryotic and eukaryotic cells?

Answer 43

cytoplasm lacks membrane bound organelles smaller ribosomes single circular DNA molecule that is free in the cytoplasm rather than a nucleus a cell wall containing murein, a glycoprotein

Question 44

what do some prokaryotes have but not all

Answer 44

one or more plasmids a capsule surrounding the cell (protects against immune system) one or more flagella - helps cell to move

Question 45

describe the properties of a virus

Answer 45

they are acelluar (not cells) they are non-living

Question 46

where do viruses reproduce?

Answer 46

inside cells of other organisms called host cells

Question 47

describe the structure of a virus

Answer 47

it has a core of genetic material it has a capsid - protein coat it has attachment proteins to allow virus to attach to host cells

Question 48

what is the equation for magnification?

Answer 48

magnification= image size/actual size

Question 49

define resolution

Answer 49

the minimum distance apart from 2 objects can be in order for them to appear as separate items

Question 50

define magnification

Answer 50

the increase in size of an object when viewed through a microscope or other optical device

Question 51

what is the source of image of an optical microscope?

Answer 51

light

Question 52

what is the maximum resolution for an optical microscope?

Answer 52

0.2um

Question 53

what is the maximum magnification for an optical microscope?

Answer 53

x1500

Question 54

how is the beam focused in an optical microscope?

Answer 54

using a lens

Question 55

in which microscopes can a live specimen be viewed?

Answer 55

only in an optical microscope

Question 56

what are the 3 types of microscopes?

Answer 56

optical microscope transmission electron microscope - TEM scanning electron microscope - SEM

Question 57

what are the advantages of a light microscope?

Answer 57

live specimen can be viewed image can be viewed directly

Question 58

is staining required in optical microscope?

Answer 58

yes

Question 59

what is the source of image for a TEM?

Answer 59

electrons

Question 60

what is the maximum resolution in a TEM?

Answer 60

0.1um

Question 61

how is the beam focused in a TEM?

Answer 61

using an EM Condenser

Question 62

what are the disadvantages of a TEM?

Answer 62

staining is required image cannot be viewed directly live specimen cannot be used

Question 63

what is the source of image for an SEM

Answer 63

electrons

Question 64

what is the maximum resolution for an SEM

Answer 64

0.002um

Question 65

how is the beam focused in an SEM

Answer 65

using an EM condenser

Question 66

what are the disadvantages of an SEM?

Answer 66

live specimen cannot be viewed image cannot be viewed staining is required

Question 67

what is an artefact?

Answer 67

artefacts could be dust, air bubbles, fingerprints etc.. made during the preparation of the specimens and can often be mistake for organelles

Question 68

what is cell fractionation?

Answer 68

used to seperate an organelle from the cell

Question 69

what are the 3 steps in cell fractionation?

Answer 69

homogenisation filtration ultracentrifugation

Question 70

what is homogenisation?

Answer 70

breaking up the cells

Question 71

what is ultracentrifugation?

Answer 71

separating the organelles

Question 72

how can homogenisation be done?

Answer 72

by vibrating the cells or put in a blender

Question 73

why is homogenisation done?

Answer 73

to break up the plasma membrane and release the organelles into solution

Question 74

why must the solution during cell fractionation be kept ice cold?

Answer 74

to reduce the enzyme activity that breaks up the organelles - so a buffer solution should be added to maintain pH

Question 75

What is the homogenate?

Answer 75

homogenised cell solution

Question 76

why is the homogenate filtered?

Answer 76

to separate out large cell debris or tissue debris that was not broken up

Question 77

after being filtered what is the solution called?

Answer 77

the filtrate

Question 78

what does the filtrate contain?

Answer 78

a mixture of organelles

Question 79

what is a centrifuge?

Answer 79

machine separating materials by spinning

Question 80

what is done after the solution is altered - (to the filtrate)

Answer 80

it is placed in a centrifuge which is first spun at low speed flinging the largest/heaviest organelles to the bottom go the tube where they form a pellet leaving the rest of the organelles in a fluid called the supernatant

Question 81

what is done to the supernatant after?

Answer 81

it is drained off and placed into another tube spun at a higher speed repeating the process of creating a pellet and a new supernatant this process is repeated until the desired organelles is seperated out

Question 82

what is the order of heaviest to lightest organelle?

Answer 82

nucleus chloroplast mitochondria lysosomes endoplasmic reticulum ribosomes