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A level Biology > Cells- Topic 2 > Flashcards

Cells- Topic 2 Flashcards

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1
Q

Magnification

A

how much the microscope can
increase the image size.

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2
Q

Resolution

A

how well you can determine the
difference between two points.

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3
Q

1m =

A

1,000mm = 1,000,000µm =
1,000,000,000nm. (x 1000)

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4
Q

Magnification =

A

size of image/ size of real object

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5
Q

Light microscope resolution

A

Low resolution due to comparatively large wavelength of light

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6
Q

Light microscope limitations

A

Samples are generally dead, Very thin sample slices are needed, The sample may have to be stained to show up important features eg, nucleus
of cell, The image is 2D

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7
Q

Transmission electron microscope

A

Highest resolution, 2D image, electron beam passes through a thin sample

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8
Q

Transmission Electron microscope limitations

A

Sample must be dead, complex staining process, thin sample, vacuum needed, complex staining process.

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9
Q

Scanning electron microscope

A

3D image, electrons bounce off sample

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10
Q

Scanning electron microscope limitations

A

lower resolution and magnification than TEM, vacuum needed, complex staining process.

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11
Q

Cell fractionation

A

the process by which cells are broken up and the different organelles they contain are separated out

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12
Q

Before homogenisation the sample is placed in a solution which is:

A

Cold, Isotonic and Buffered

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13
Q

Homogenisation

A

Blending the sample to release the cells contents

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14
Q

Filtration

A

Removes impurities from the sample

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15
Q

Ultracentrifugation

A

Spun to form sediment pellets of heaviest component and supernatant which can be respun

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16
Q

Nuclear envelope

A

a double membrane surrounding the nucleus with nuclear pores to control the exit of substances

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17
Q

nucleoplasm

A

semifluid matrix which contains chromatin (less condensed form of DNA)

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18
Q

Nucleolus

A

Centre of the nucleus, produces ribosomes

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19
Q

Nucleus function

A

Controls functions of the cell

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20
Q

Mitochondria function

A

Site of aerobic respiration, produces ATP

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21
Q

Mitochondria double membrane

A

Inner and outer membranes, Controls entry and exit of material

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22
Q

Mitochondria Cristae

A

Extensions of inner membrane (folds), Provide large surface area (attachments of
enzymes and proteins)

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23
Q

Matrix (Mitochondria)

A

Space between cristae, Contains protein, lipids, ribosomes, DNA, enzymes.

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24
Q

Chloroplasts function

A

Site of Photosynthesis

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25
Q

Chloroplast envelope

A

double plasma membrane: outer and inner
membrane, selective, choose what can enter and leave

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26
Q

Thylakoids (chloroplasts)

A

Membranous sacs which contain photosynthetic pigment called chlorophyll (capture light), ATP is made here,

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27
Q

Grana (chloroplasts)

A

stacks of up to 100 disk like thylakoids,

28
Q

lamellae (chloroplasts)

A

connecting tubes between thylakoids

29
Q

Stroma (chloroplasts)

A

fluid-filled matrix where sugars are made from carbon dioxide

30
Q

Rough Endoplasmic Reticulum structure

A

A system of membranes enclosing a fluid-filled space studded with numerous ribosomes

31
Q

Rough Endoplasmic Reticulum function

A

pathway for transport of materials (proteins) folds and processes proteins that have been made at the ribosomes

32
Q

Smooth Endoplasmic reticulum structure

A

A system of membranes enclosing a fluid-filled space, no ribosomes

33
Q

Smooth Endoplasmic reticulum function

A

synthesise, processes, store and transport lipids and carbohydrates

34
Q

Golgi apparatus structure

A

A group of fluid-filled, membrane-bound
flattened sacs. Vesicles are often seen at the edges of the sacs

35
Q

Golgi apparatus function

A

processes and packages new lipids and
proteins, forms glycoproteins. It also makes lysosomes

36
Q

Golgi Vesicle structure

A

small fluid-filled sac in the cytoplasm, surrounded by a membrane and produced by the Golgi apparatus

37
Q

Golgi Vesicle function

A

Stores lipids and proteins made by
the Golgi apparatus and transports
them out of the cell (via the
cell-surface membrane)

38
Q

Lysosome structure

A

Formed when vesicles from Golgi body contain enzymes (protease and lipase and lysozyme)

39
Q

Lysosome function

A

Hydrolyse material ingested by phagocytic cells (white blood cell, bacteria), Release enzymes to the outside of cell (exocytosis) to destroy material around the cell, Digest worn out organelles, Autolysis – completely break down cells after they have died

40
Q

Ribosomes structure

A

Made of proteins and rRNA, Two subunits – large and small. 80s in eukaryotes, 70s in prokaryotes

41
Q

Ribosome function

A

Site of protein synthesis

42
Q

Cell wall structure and function

A

Microfibrils of polysaccharide embedded in a
matrix, provides mechanical strength

43
Q

Cell membrane function

A

selectively permeable barrier

44
Q

Vacuole structure and function

A

membrane-bound organelle found in the cytoplasm of plant cells containing cell sap. surrounding membrane is called a tonoplast. Helps to maintain pressure inside the cell and keep the cell rigid, isolates unwanted chemicals.

45
Q

substance in bacterial cell wall

A

murein

46
Q

DNA store in prokaryotes

A

circular strand of DNA and plasmids

47
Q

How do bacteria divide

A

binary fission

48
Q

flagella

A

tail that some bacteria have

49
Q

Capsule

A

Outer layer of bacterial cells

50
Q

viruses

A

acellular, non living particles

51
Q

virus structure

A

Contain nucleic acids, DNA and RNA, enclosed within a protein coat called the capsid

52
Q

G1 of cell cycle

A

cell contents duplicated

53
Q

S of cell cycle

A

DNA duplicates

54
Q

G2 of cell cycle

A

checking DNA replication and preparing to divide

55
Q

centromere

A

where 2 sister chromatids are joined

56
Q

interphase

A

chromosomes duplicate so there is double the amount of genetic information

57
Q

Prophase

A

prepare. DNA super coils and chromosomes become visible. Nuclear membrane breaks down. Centrioles divide (to form 4) and spindle is assembled

58
Q

centriole

A

organises the spindle fibres

59
Q

Metaphase

A

middle. Chromosomes line on equator of cell Spindles fibres attach to centromeres

60
Q

anaphase

A

apart. Centromere splits Chromatids are pulled to opposite poles as spindle
fibres contract

61
Q

telaphase

A

two. Nuclear membranes reform Chromosomes uncoil Cytokinesis begins

62
Q

Cytokinesis

A

cell divides to form 2 daughter cells

63
Q

what causes tumours and cancer

A

uncontrolled cell division

64
Q

how do viruses replicate

A

by injecting their nucleic acid into host cells

65
Q

mitotic index

A

the proportion of cells (in a group of cells or a
sample of tissue) that are undergoing mitosis. The more rapidly the cells are dividing, the higher the index

66
Q

mitotic index calculation

A

number of cells in mitosis/ total number of cells

67
Q
A

A level Biology (8 decks)

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