Cell Structure & Division (Chapter 3) Flashcards

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1
Q

What is a eukaryotic cell?

A

Animal cell
Plant cell
Algal cells
Fungal cells

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2
Q

What is a prokaryotic cell?

A

Bacteria lol

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3
Q

Function of the cell surface membrane?

A

Regulates movement of substances in and out of the cell.
Has receptors which allow it to respond to hormones etc

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4
Q

Structure of the nucleus?

A

Large organelle surrounded by a nuclear envelope which contains pores.
Nucleus contains chromosomes (made from protein bound linear DNA)

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5
Q

Function of the nucleus?

A

Controls cells activities
DNA of course babe
Contains instructions to make proteins

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6
Q

Structure of mitochondria?

A

Double membrane- inner highs folded (cristae)
Matrix- contains enzymes involved in respiration

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7
Q

Function of mitochondria?

A

Site of aerobic respiration
ATP produced

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8
Q

Structure of chloroplasts?

A

Small flattered structure
Double membrane
Thylakoid membranes- stacked up to form grana
Lamella

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9
Q

Function of chloroplasts?

A

Photosynthesis

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10
Q

Structure of Golgi vesicle?

A

Small fluid filled sac in the cytoplasm surrounded by a membrane

Produced by Golgi apparatus

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11
Q

Function of Golgi vesicle?

A

Stores lipids and proteins made by Golgi apparatus
Transports these out the cell

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12
Q

Lysosome structure?

A

Round organelle
Membrane

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13
Q

Function of lysosomes?

A

Contains hydrolysis enzymes

Used to digest invading cells or break down worn out cell parts

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14
Q

Ribosome structure?

A

Small organelle made up of proteins and RNA

NO MEMBRANE

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15
Q

Ribosome function?

A

Proteins are made

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16
Q

Rough endoplasmic reticulum structure?

A

System of membranes enclosing fluid filled space

Covered with ribosomes

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17
Q

Function of RER?

A

Folds and processed proteins

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18
Q

Smooth endoplasmic reticulum structure?

A

Membranes enclosing a fluid filled space

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19
Q

SER function?

A

Synthesises proteins and lipids

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20
Q

Cell wall structure?

A

Rigid structure surrounds cells in plants, algae, fungi

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21
Q

What Is the cell wall in plants and algae made of?

A

Cellulose

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22
Q

What is the cell wall made of in fungi?

A

Chitin

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23
Q

Cell wall function?

A

Give support- preventing from changing shape

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24
Q

Cell vacuole structure?

A

Membrane bound found in cytoplasm of plant cells
Contains cell sap

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25
Q

Function of cell vacuole?

A

Maintain pressure inside cell and keep cell rigid

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26
Q

Where do cells become specialised?

A

In complex multicellular organisms

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27
Q

How are specialised cells organised?

A

Cells —> tissues —> organs —> organ systems —> organisms

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28
Q

Give one example of a specialised cell?

A

Epithelial cells in small intestine- food absorption

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29
Q

List 4 ways prokaryotic cells differ to eukaryotic cells?

A

Cytoplasm lacks membrane bound organelles

Smaller ribosomes

No nucleus- instead they have loop & plasmids (sometimes)

Cell wall that contains Muriein (glycoproteins)

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30
Q

What are the three things that only certain prokaryotic cells have?

A

One or more plasmid

Capsule surrounding the cell

One or more flagella

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31
Q

Are viruses cells?

A

NO they are acellular

32
Q

Structure of a virus? And what do they contain?

A

Nucleic acids surrounded by a protein coat

Genetic material
Capsid
Attachment proteins

33
Q

Magnification equation?

A

Magnification = size of image / size of real object

34
Q

What is magnification?

A

How much bigger the image is than the specimen

35
Q

What is resolution?

A

How well a microscope can distinguish between two points that are close together

36
Q

Optical microscopes max resolution?

A

0.2 um

37
Q

What is the max useful resolution on an optical microscope?

A

X1500

38
Q

What is the max resolution on an electron microscope?

A

0.0002 um

39
Q

What is the max useful magnification on an electron microscope?

A

X 1 500 000

40
Q

How do transmission electron microscopes work?

A

Use electromagnets to focus a beam of electrons, which is then transmitted through the specimen.

Denser parts of the specimen absorb more electrons which makes them look darker on the image

41
Q

Advantage of transmission electron microscope?

A

High resolution images, so can see things like organelles (eg. Chloroplasts)

42
Q

Disadvantage of transmission electron microscopes?

A

Can only be used on thin specimens

43
Q

How do scanning electron microscopes work?

A

Scan a beam of electrons across the specimen which knocks off electrons from the specimen. These knock off electrons from the specimen which are gathered in a cathode ray tube to form an image.

44
Q

Are SEMs images 3D or 2D?

A

3D

45
Q

Advantage of SEMs?

A

Can be used on thick specimens

46
Q

Disadvantage of SEMs?

A

Lower resolution than TEMs

47
Q

If you wanted to look at organelles under an electron microscope what technique would you use?

A

Cell fractionation

48
Q

List the three steps involved in cell fractionation?

A

Homogenisation

Filtration

Ultracentrifugation

49
Q

What is involved in homogenisation?

A

Breaking up the plasma membrane and releases the organelles into the solution

50
Q

What is the solution in homogenisation and why?

A

Ice cold- reduce enzyme activity

Isotonic- prevent damage through osmosis/ stop osmosis

Buffered- maintain pH

51
Q

What is involved in filtration?

A

Homogenised cell solution is filtered through a gauze to separate any large debris eg. Connective tissue

52
Q

Describe the three steps of ultracentrifugation?

A

Cell fragments poured into a tube, then added to a centrifuge and spun at low speed. Heaviest organelles go to the bottom (nuclei) and form the pellet. The other organelles and solution is called the supernatant.

Supernatant drained off and poured into another tube. Then spun again in the centrifuge at a higher speed. Heaviest form pellet (this time mitochondria).

Process repeated again at higher and higher speeds until all organelles separated out.

53
Q

What are artefacts?

A

Things that you can see down the microscope that aren’t part of the cell or specimen eg. Dust or fingerprints etc

54
Q

Where are artefacts most common?

A

In electron micrographs

55
Q

Can we distinguish between artefacts and the specimen?

A

Kinda, there was a considerable period of time when we couldn’t tho

56
Q

What is mitosis?

A

Cell division in eukaryotes that produces genetically identical cells

57
Q

What are the four stages of mitosis?

A

Prophase

Metaphase

Anaphase

Telophase

58
Q

What is mitosis needed for?

A

Growth of multicellular organisms and repairing damaged tissues

59
Q

What is the period of cell growth, DNA replication and ATP content increased called?

A

Interphase

60
Q

What is a centromere?

A

The bit in the middle where the chromatids join

61
Q

What happens in prophase? (3 point)

A

Chromosomes condense and get shorter and fatter

Centrioles start moving to opposite ends of the cell, forming spindle fibres

Nuclear envelope breaks down (chromosomes free in cytoplasm)

62
Q

What happens in metaphase?

A

Chromosomes (each with two chromatids) line up along the middle of the cell and become attached to the spindle by their centromere

63
Q

What happens in anaphase? (3 points)

A

Centromeres divide, separating each sister chromatids.

Spindles contract pulling chromatids to opposite poles (centromere first)

Chromatids appear v shaped

64
Q

What happens in telophase? (5 points)

A

Chromatids reach opposite poles

Uncoil and become long and thin again (now called chromosomes)

Nuclear envelope forms (now two nuclei)

Cytokinesis finished in telophase

Two daughter cells formed

65
Q

What is cancer the result of?

A

Uncontrolled cell division

66
Q

What is cancer?

A

Tumour that invades surrounding tissue

67
Q

What are both mitosis and the cell cycle controlled by?

A

Genes

68
Q

What are cancer treatments usually aimed at?

A

Control the rate of the cell cycle

69
Q

What is chemotherapy targeted at (chemical drugs)?

A

Prevents synthesis of enzymes needed for DNA replication- forcing cell to kill itself

70
Q

What is radiation targeted at?

A

Damage DNA which when the body checks for damage the cell will kill itself

71
Q

How do prokaryotic cell replicate?

A

Binary fission

72
Q

How do viruses replicate themselves?

A

They use host cells- inject their DNA or RNA into host cell LOL

Inject nucleic acid as well

Host cell replicates virus particles

73
Q

List the 4 steps involved in binary fission?

A

Circular DNA and plasmids replicate, main loop only replicated once

Cell gets bigger and DNA loops move to opposite poles

Cytoplasm begins to divide and new cell walls begin to form

Cytoplasm divides and two daughter cells are produced (each has one copy of circular DNA but variable NO of plasmids)

74
Q

What is the equation for mitotic index?

A

Mitotic index = number of cells with visible chromosomes / total number of cells observed

75
Q

What required practical is used for mitosis?

A

Preparation of stained squashes of cells from plant root tips and using an optical microscope to identify stages of mitosis

Calculate mitotic index

76
Q

What is an eyepiece graticule used for?

A

Calculate the size of cells

77
Q

Does an eyepiece graticule need to re-calibrated at each magnification?

A

Of course