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Biology > 1. Cells and cell techniques > Flashcards

1. Cells and cell techniques Flashcards

1
Q

What do all cells contain

A
  • A cell-surface membrane
  • Cytoplasm
    -Genetic material, made of DNA
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2
Q

What are the two groups cells can be divided into

A

-Prokaryotic: Bacteria
- Eukaryotic: Cells found in plants, fungi, algae and animals that have internal membranes, forming organelles

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3
Q

What is an organelle

A

Small structure in cytoplasm that has a specific function

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4
Q

What are differences between prokaryotes and eukaryotes

A

Prokaryotes are much smaller
Prokaryotes don’t contain any membrane-bound organelles in their cytoplasm

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5
Q

How to prokaryotes from new cells

A

Binary Fission

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6
Q

What are the structures of a bacterium cell

A

Capsule (MBP)
Cell wall
Cell surface membrane
Cytoplasm
Small ribosomes
Plasmids (MBP)
DNA
Flagellum (MBP)

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7
Q

What is the DNA of a bacterium cell like

A

Short, circular molecule of DNA
Not associated with protein
Free in the cytoplasm

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8
Q

What is the function of DNA of a bacterium cell

A

Carries genetic codes for proteins

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9
Q

What is the cell wall of a bacterium like

A

Contains Murein - a glycoprotein

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10
Q

What is the function of the cell wall of a bacterium cell

A

Prevents osmotic lysis
Rigid - strengthening

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11
Q

What is cytoplasm in a bacterium cell like

A

A solution where many dissolved molecules are found
No membrane-bound organelles

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12
Q

What is the function of the cytoplasm in a bacterium cell

A

Site of many metabolic reactions

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13
Q

What is the cell surface membrane of a bacterium cell like

A

Phospholipid bilayer with embedded proteins

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14
Q

What is the function of the cell surface membrane in a bacterium cell

A

Controls passage of substances across exchange surfaces by passive or active transport

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15
Q

What is the function of the small ribosomes in a bacterium cell

A

Protein synthesis

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16
Q

What are simple flagellum like in a bacterium cell

A

Thin rotating fibres

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17
Q

What is the function of simple flagella in a bacterium cell

A

Responsible for movement of cell

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18
Q

What are plasmids like in a bacterium cell

A

One or more small loops of DNA
Can replicate independently

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19
Q

What is the function of Plasmids in a bacterium cell

A

Can pass on genetic info via conjugation to other bacteria

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20
Q

What is the capsule like in a bacterium cell

A

Extra layer outside the cell wall

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21
Q

What is the function of the capsule in a bacterium cell

A

Protects from desiccation, phagocytosis and some pathogens

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22
Q

How do we know that eukaryotes evolved from prokaryotes

A

Eukaryotes have extra features

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23
Q

What is the benefit of having membrane-bound organelles in eukaryotes

A

Allows chemical reactions to take place quickly and efficienctly

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24
Q

How to eukaryotes form new cells

A

Mitosis and meiosis

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25
Q

What is the plasma membrane like in a eukaryote

A

Found of cell surface and most internal organelles.
Made of a phospholipid bilayer which also contains embedded proteins

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26
Q

What is the function of the plasma membrane in eukaryotic cells

A

Selectively permeable
Allows cell identification

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27
Q

What is the nucleus like in eukaryotes

A

Contains chromosomes which are long, linear DNA molecules
Associated with histone protein
Has one or more neucleoli

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28
Q

What is the function of the nucleus in a eukaryote

A

DNA contains genetic code for making proteins
Nucleolus manufactures ribosomes

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29
Q

What is a mitochondrion like in a eurkaryote

A

Oval shaped organelle surrounded by 2 membranes.
Inner membrane folds and forms cristae
Fluid inside is called the matrix
Contains DNA like that in Prokaryotes

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30
Q

What is the function of mitochondria in eukaryotes

A

Produce ATP from aerobic respiration
ATP used by cell far active processes like protein synthesis

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31
Q

What is the Rough endoplasmic reticulum like in a eukaryote

A

A series of tubes in the cytoplasm of a cell.
Appears rough due to the ribosomes attached to the membranes

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32
Q

What is the function of the RER in a eukaryote

A

Synthesis and transport of proteins through cytoplasm

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33
Q

What are ribosomes like in a eukaryote

A

80s
Made of RNA and protein. Not surrounded by a membrane

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34
Q

What is the function of ribosomes in eukaryotes

A

Protein synthesis

35
Q

what is the smooth endoplasmic reticulum like in a eukaryote

A

A series of tubes in the cytoplasm of cell
No ribosomes attached

36
Q

What is the function of the SER in a eukaryote

A

Synthesises and transports lipids

37
Q

What is the golgi apparatus and vesicles like in eukaryotes

A

Stacks of flattened sacs.
Vesicles are continually budded off from the ends of the sacs

38
Q

What is the function of the Golgi apparatus and vesicles in a eukaryote

A

Modifies proteins that are made in the cell e.g coverts them to glycoproteins
Packages them into vesicles
Forms lysosomes

39
Q

What is a lysosome like in a eukaryote

A

Golgi vesicle
Contains hydrolytic enzymes, sometimes known as lysozymes

40
Q

What is the function of lysosomes in a eukaryote

A

Digest unwanted material in the cell like pathogens or unwanted organelles

41
Q

What structures do plant cells have that animal cells dont

A

Cell wall
Vacuole
Chloroplasts

42
Q

What is the function of a plant cell wall

A

Made of cellulose
Provides high tensile strength that prevents osmotic lysis
Cell wall in Fungi is made of Chitin

43
Q

What is the function of a vacuole in a plant cell

A

Filled with cell sap
Gives rigidity

44
Q

What is the function of chloroplasts in a plant cell

A

Site of photosynthesis

45
Q

Where are chloroplast cells found

A

The mesophyll cells of leaves of green plants

46
Q

What are the structures of a chloroplast

A

Envelope
Granum
Stroma
DNA
Ribsomes

47
Q

What is the function of a chloroplast envelope

A

A double-membrane surrounding the chloroplast

48
Q

What is the function of Granum in chloroplasts

A

A stack of membrane-bound discs called thylakoids
Thylakoid membranes contain chlorophyll
Membranes provide large SA for light absorption to maximise photosynthesis

49
Q

What is the function of the Stroma in chloroplasts

A

Contains enzymes needed for photosynthesis and stores starch grains

50
Q

What is the function of DNA in chloroplasts

A

Short, circular and not associated with proteins

51
Q

What size are the ribosomes in a chloroplast

A

70s

52
Q

What is a tissue

A

A group of similar cells

53
Q

What is an organ

A

A group of tissues

54
Q

What is an organ system

A

A group of interacting, interrelated, or independent organs forming a complex functional whole

55
Q

What are viruses

A

They’re not cells and so are non-living.
Acellular
Cant undergo cell division - need to attach and enter a host cell and use that cell’s machinery

56
Q

What components are viruses made up of

A

Genetic material
Capsid
Attachment protein

57
Q

What is the genetic material of a virus

A

either DNA or RNA

58
Q

What is a capsid in a virus

A

A protein coat

59
Q

What is an attachment protein in a virus

A

Allows the virus to attach to host cell
Complementary to receptors of host cell membrane

60
Q

What is magnification

A

The number of times bigger the image appears compared to its actual size

61
Q

What is resolution

A

The minimum distance between 2 objects / points at which they can be seen as separate

62
Q

What does an optical microscope consist of

A

Use light to illuminate and glass lenses to focus light
Eyepiece lens of fixed magnification and selection of objective lenes of various magnifications
One-cell-thick specimen

63
Q

What resolution for light microscopes have

A

Have a relatively long wavelength so the resolution is low

64
Q

What does an electron microscope consist of

A

Beam of e- which are focused using a series of electromagnets

65
Q

What is the resolution of an electron microscope

A

e- have a smaller wavelength so resolution is higher

66
Q

What are the different types of electron microscopes

A

Transmission electron microscope (TEM)
Scanning electron microscope (SEM)

67
Q

What is a transmission electron microscope

A

The beam of electrons is transmitted through a very thin specimen

68
Q

What can be looked at under a TEM

A

The greater resolution means smaller organelles such as ribosomes can be observed as well as internal details of organelles

69
Q

What is a scanning electron microscope

A

Used to study 3D objects. The e- are reflected off the surface rather than passing through

70
Q

What are the advantages of using light microscopes

A

Colour of images
Living specimens
Prep of specimens is simple

71
Q

What are the limitations of using light microscop[es

A

Lower resolution
Limited by wavelength of light
Lower magnification

72
Q

What are the advantages of using an electron microscope

A

Higher resolutionas e- beam wavelength is shorter than light.
Higher magnification
Finer detail can be seen

73
Q

What are the limitations of using electron microscopes

A

Black and white images only
Vacuum is needed so only dead specimens
Complex preparation of specimens often results in artefacts
TEM require thin specimen

74
Q

What is an artefact

A

Something that results from the way a specimen is prepared. May appear on micrograph but not be part of the natural specimen.

75
Q

How do you convert between mm-um-nm

A

mm-x10^3-um-x10^3-nm

76
Q

How do you calculate magnification and how is it measured

A

I=AM (mm)

77
Q

How can you determine an organelle function

A

Must be isolated from the cell by cell fractionation and ultracentrifugation

78
Q

What happens in cell fractionation

A
  • Cells broken pen using homogeniser - breaks cell membranes and allows the organelles to be released
  • Cell debris and whole cells are filtered off to leave a suspension
79
Q

What happens during ultracenrtifugation

A

-Resultant suspension is centrifuged at a low speed
-The most dense organelle (Nucleus) separates out at the bottom of the tube. The rest of the organelles are still suspended in the supernatant
-Supernatant is poured into fresh tube and spun at a higher speed to separate (chloroplasts) mitochondria
-Process is repeated at increasing speeds to separate off the less dense organelles. A very high speed will be needed for ribosomes

80
Q

What conditions are held during the separation of organelles

A

Cold temperature
Buffer
Isotonic

81
Q

Why are cold temperatures needed when separating organelles

A

Reduces enzyme activity so no digestion of organelles by lysozymes

82
Q

Why is a buffer needed in organelle separation

A

Maintains constant pH to prevent denaturation of proteins including enzymes

83
Q

Why does organelle separation need to be kept isotonic

A

Same as water potential as organelles to prevent osmotic lysis or shrinking of organelles

Biology (23 decks)

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