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As level biology main topics Paper 1 > B3 Cell Structure > Flashcards

B3 Cell Structure Flashcards

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1
Q

Equation for magnification?

A

(Size of image)/(Size of real object)

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2
Q

Trend for unit conversion for bellow mm?

A

Divide 1000

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3
Q

What is the definition for resolution?

A

Ability to distinguish two points on an image

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4
Q

What are the properties of the solution that cells are placed in before cell fractionation?

A

Cold - reduce enzyme activity that may break down organelle; Same water potential - prevent organelle bursting or shrinking; Buffered - pH doesn’t fluctuate as it could alter structure of organelle

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5
Q

What are the 2 stages of cell fractionations?

A

Homogenisation and Ultracentrifugation

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6
Q

What occurs in homogenisation?

A

Cells are broken by homogeniser, this released organelle from cell, homogenate is then filtered to remove any complete cells and large pieces of debris

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7
Q

What is homogenate ?

A

Resultant fluid from homogeniser

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8
Q

What is ultracentrifugation?

A

Process by which fragments in the filtered homogenate are separated in a centrifuge

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9
Q

What is the method for ultracentrifugation of an animal cell?

A

Tube of filtrate placed in centrifuge at low speeds; Heaviest organelle, nuclei are forced to bottom of tube, they form thin sediment; supernatant is removed, leaving nuclei; supernatant transferred to another tube and spun in centrifuge at higher speeds;

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10
Q

What is supernatant?

A

Soluble liquid fraction of a sample after centrifugation or precipitation of insoluble solids.

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11
Q

What are the order of cells that are homogenised from first?

A

Nuclei, Mitochondria, Lysosomes

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12
Q

What are the advantages of an electron microscope over a light microscope?

A

Electron beam has very short wavelength allowing for high resolution; Electrons are negatively charged so can be focused using electro magnet

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13
Q

What is the differences between TEM and SEM

A

SEM (Electrons reflect off surface; Black and white image; Super magnified view; Lower resolution but 3D) TEM (Specimen thin slices; electrons pass through; coloured image; higher resolution)

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14
Q

What do you use an eyepiece graticule for?

A

Measuring size of objects

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15
Q

How do you calibrate the eyepiece graticule?

A

Stage micrometer, has scales etched onto it

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16
Q

What is an ultrastructure?

A

Each cell type has an internal structure that suits its job

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17
Q

What is the ultrastructure of a eukaryotic cell?

A

Distinct nucleus , membrane bound organelle

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18
Q

What does the nucleus contain in a prokaryotic cell?

A

Hereditary material and controls cell’s activities

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19
Q

What are the structures of a nucleus?

A

Nuclear envelope, Nuclear pores, Nucleoplasm, Chromosomes, nucleolus

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20
Q

What does the nuclear envelope do?

A

Double membrane surrounds nucleus, outer membrane has endoplasmic reticulum and ribosomes; controls entry and exit of materials; contains reactions taking place within

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21
Q

What do the nuclear pores do?

A

Allow passage of large molecules, mRNA out of nucleus

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22
Q

What does the nucleoplasm do?

A

is the granular; jelly like material that makes up bulk of nucleus

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23
Q

What does the chromosomes do?

A

Consist of protein bound linear DNA

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24
Q

What does the nucleolus do?

A

Small spherical region within nucleoplasm, manufacture ribosomal RNA , assembles ribosomes, may be multiple in 1 nucleus

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25
Q

What does the nucleus do?

A

Control centre via production of mRNA, tRNA , protein synthesis; retain genetic material in form of DNA and chromones; manufacture ribosomal RNA and ribosomes

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26
Q

What are the structures of Mitochondrion?

A

Double membrane, Cristae, Matrix

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27
Q

What does the double membrane in mitochondrion do?

A

Control entry and exit of material, inner two membranes is folded to form extension known as cristae

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28
Q

What does the cristae do?

A

Extensions of inner membrane, large surface area for attachment of enzymes and other protein involved respiration

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29
Q

What does the cristae do?

A

Remainder of mitochondrion, contains proteins, lipids, ribosomes, DNA; allows mitochondria to control production of some of their own proteins , many enzymes of respiration are found here

30
Q

What do mitochondria do?

A

Sites of aerobic stages of respiration , production of ATP

31
Q

What are the structures of chloroplasts?

A

Chloroplast envelope, The grana - thylakoids - chlorophyll, The stroma

32
Q

What does the chloroplast envelope do?

A

double plasma membrane, highly selective in what it allows inside and outside chloroplast

33
Q

What does the grana do?

A

stacks of up to 100 disc like structures called thylakoids, chlorophyll is contained inside the thylakoids, tubular extensions that join adjacent grana by thylakoids, first site of photosynthesis takes place here (light absorption)

34
Q

What does the stroma do?

A

Fluid filled matrix , second stage of photosynthesis takes place (sugar synthesis), number of other structure within such as starch grains

35
Q

How are chloroplasts adapted for photosynthesis?

A

grana membrane - large surface area for chlorophyll, electron carriers , enzymes for first stage; fluid in stroma has enzymes for second stage; contains DNA and ribosomes - produce protein needed for photosynthesis

36
Q

What are the structures of the endoplasmic reticulum?

A

Membrane enclose network of flattened sacs and tubules called cisternae; Rough endoplasmic reticulum; smooth endoplasmic reticulum

37
Q

What does RER do?

A

ribosomes on surface of membrane; large surface area - synthesis of proteins , glycoproteins; pathway for transport of materials - proteins

38
Q

What does SER do?

A

lacks ribosomes on surface, more tubular in shape; synthesise, transport, store lipids; synthesise, transport, store carbohydrates

39
Q

What is the structure of the golgi aparatus?

A

Similar to SER, more compact; stacks of membranes that make up flattened sacs (cisternae); small round hollow vesicles;

40
Q

How do proteins and lipids from RER interact with golgi apparatus?

A

Lipids, proteins produced by RER passed through golgi in a strict sequence, modifies molecules often adding non protein molecules - carbs; labels molecules, labeled molecules are sent to golgi vesicles; vesicle moves to cell surface membrane , fuses then releases contents outside of cell.

41
Q

What are the functions of the golgi aparatus?

A

Add carbohydrates to proteins forming glycoproteins; produce secretory enzymes - secreted by pancreas; secrete carbohydrates, making cell walls; transport, modify, store lipids; form lysosomes

42
Q

How are lysosomes produced?

A

vesicles produced by Golgi apparatus contain enzymes - protease, lipases;

43
Q

What do lysozymes do?

A

hydrolyse cell walls of certain bacteria

44
Q

What are the functions of lysosomes?

A

hydrolyse material ingested by phagocytic cells, white blood cells, bacteria; exocytosis (release enzyme outside of cell)- destroy material outside of cell; digest worn out organelle, chemicals can be reused; autolysis (break down dead cells)

45
Q

What are the 2 types of ribosomes?

A

80s - found in eukaryotic cell 25nm diameter; 70s - found in prokaryotic cells, mitochondria, chloroplasts, smaller slightly

46
Q

What are cell walls consisted of?

A

number of polysaccharides such as cellulose; middle lamella, thin layer marking boundary between adjacent cell walls, and cements them together

47
Q

What are the functions of the cell wall?

A

provide mechanical strength, prevent cell bursting under pressure from osmotic entry of water; mechanical strength to plant as whole; allow water to pass along it, contribute to movement of water throughout plant

48
Q

What are cells walls of algae made of?

A

cellulose or glycoprotein, or a mixture

49
Q

What are cell walls of fungi made of?

A

chitin, glycan and glycoproteins

50
Q

Describe the structure of a vacuole.

A

fluid filled sac bounded by a single membrane

51
Q

What is a tonoplast?

A

single membrane that surrounds a large vacuole

52
Q

What are the functions of a vacuole?

A

support herbaceous plants by making cells turgid; sugar and amino acids may act as temp food source; pigments may colour petals to attract pollinating insects

53
Q

What are bacterial cell walls comprised of?

A

Murein

54
Q

What are the structures found inside a bacterium cell?

A

Cell wall, capsule, cell surface membrane, circular DNA, plasmid

55
Q

How are eukaryotic cells mainly different from prokaryotic cells?

A

No true nucleus, DNA is not associated with proteins, no membrane bound organelle, ribosomes smaller (70s)

56
Q

What proteins are DNA from eukaryotic cells associated with?

A

Histones

57
Q

What are the structures found on and in a virus?

A

Attachment proteins on lipid envelope, matrix under lipid envelope, capsid surrounded by matrix, RNA and reverse transcriptase within capsid

58
Q

What is mitosis?

A

Division of cells producing 2 daughter cells, same number of chromosomes as parent cell

59
Q

What is meiosis?

A

Division of cells producing 4 daughter cells , each with half number of chromosomes as parents

60
Q

What are the phases of mitosis ?

A

IPMAT, Interphase Prophase Metaphase Anaphase Telophase

61
Q

What occurs in interphase?

A

Period between division; cells metabolically active; amount of DNA doubles in nucleus; new organelle made, mitochondria

62
Q

What occurs in interphase?

A

No chromosomes visible; Chromatins (chromosomes material) spread through nucleus in diffuse form

63
Q

What occurs at the start prophase ?

A

Longest stage; chromosomes become visible; centrioles divide, move to opposite ends of nucleus; protein microtubules develop from each centriole, spindle fibres;

64
Q

What occurs at the end of prophase?

A

Chromosomes can be seen consisting of 2 chromatids held together by centromere nucleolus disappears as nuclear envelope breaks down

65
Q

What occurs in metaphase?

A

Chromosomes line up at equator of spindle; attach to spindle by their centromere

66
Q

What occurs in anaphase?

A

Centromeres divide; spindle fibres contract; free chromatids move to poles; spindle fibres shorten chromatids get pulled apart

67
Q

What occurs in telophase?

A

Chromatids reach poles , regarded as distinct chromosomes; nuclear envelope forms around each group of chromosomes; chromosomes uncoil returning to chromatins; cytoplasm divides by cytokinesis

68
Q

What is cell division in prokaryotes called?

A

Binary fission

69
Q

How do viruses replicate?

A

Attach to host cell via attachment proteins; inject nuclei with nucleic acid; genetic information makes host cell produce viral components

70
Q

What are the stages of the cell cycle?

A

Interphase, G1 - proteins are synthesised, S- DNA is replicated, G2 - Organelle grow and divide and energy stores are increased; Nuclear division, Mitosis or Meiosis; Division of cytoplasm (cytokinesis), Cell divides

As level biology main topics Paper 1 (2 decks)

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