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A- Level Biology > C2- Cell biology > Flashcards

C2- Cell biology Flashcards

1
Q

What are the 4 main types of slide preparation?

A

Wet mount- Specimen submerged in water and cover slip added
Dry mount- Specimen placed onto slide directly and cover slip placed on top
Squash slides- Wet mount prepared and cover slip is used to squash the cells
Smear slides- Edge of a slide is used to create a smooth thin layer of cells over a slide.

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2
Q

What is magnification

A

the number of times larger an
image is compared with the real size of the object.

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3
Q

What is resolution

A

the ability to distinguish between
two separate points. If two points cannot be resolved
they will be seen as one point, eg. like car headlights

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4
Q

Light Microscope advantages (5)

A

Can be used to look at cells and large organelles within cells

Staining cells makes organelles clearer

Preparation quick and simple

Natural colour of material observed

Living tissues can be observed

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5
Q

TEM vs SEM

A

TEM passes a beam of electrons through the specimen

SEM fires a beam of electrons across the surface, which
are reflected, and then collected

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6
Q

Transition electron microscopy

A

2D image

Max Magnification = x 500,000

Better resolving power– 0.5nm

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7
Q

Scanning electron microscopy

A

3D image

Max Magnification =x 100, 000

Less resolving power = 3-10nm

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8
Q

Methylene Blue stain

A

Positively charged dye attracted to negatively charged molecules

Stains DNA

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9
Q

Differential staining

A

Used to distinguish between 2 types of organisms, or organelles within an organism

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10
Q

Positively charged stains

A

Crystal violet

Methylene Blue

Attracted to negatively charged materials in the cytoplasm

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11
Q

Dry mount

A

used with whole or sectioned specimens

Can see living organisms

Mounts are temporary unless you seal the coverslip

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12
Q

Wet Mount

A

Specimens suspended in liquids such as oil or water

Cover slip placed at an angle

Greater refraction due to the liquid
-> Greater magnification and resolution

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13
Q

Squash slide

A

Wet mount first prepared

Gently press down on cover slip

Good for softer samples such as roots

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14
Q

Smear slide

A

Edge of a slide is used to smear a sample creating a thin even coating

Cover slip then placed

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15
Q

Negatively Charged Dyes

A

Congo Red

Nigrosin

Repelled by negatively charged cytosol
-> Stays outside cells, makes them stand out

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16
Q

Differential staining

A

Aids distinguishing between organisms or organelles

Gram stain technique

Acid fast technique

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17
Q

Prepared slide types (4)

A

1- Fixing= formaldehyde used to preserve
2- Sectioning= Dehydrate, wax and then slice with a microtome
3- Staining
4- permanent mounting

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18
Q

Cytoplasm- Structure

A

Contains Enzymes

Fluid = Cytosol

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19
Q

Cytoplasm- Function (3)

A

Where chemical reactions for cells take place

Holds membrane bound compartments (organelles)

Metabolism
-> Catabolism+ Anabolism. Break down and building of molecules

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20
Q

Nucleus- Structure (4)

A

Dark patches= Chromatin

Double membrane= nuclear envelope

Nuclear pores -> RNA can leave though as DNA too large

Nucleolus inside

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21
Q

Nucleus- Function (4)

A

Contains genetic material

Chromatin= histones (proteins) forms complex with DNA. Coils and then condenses into chromosomes

Contains instructions to make proteins

When cells divide chromatin condenses to visible chromosomes

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22
Q

Nucleolus (4)

A
  • Inside Nucleus

-Composed of proteins + RNA

-Produces ribosomes

  • RNA used to produce ribosomal DNA (rRNA) combined with proteins to make ribosomes
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23
Q

Mitochondria- Structure (4)

A
  • 2 membranes separated by a fluid filled space
  • Inner membrane folded to cristae. The inner fluid is the Matrix
  • Membrane holds respiration energy

-Own DNA (mtDNA) and own enzymes

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24
Q

Mitochondria- Function

A

Where ATP is produced during respiration

25
Vesicles
Single membrane with fluid inside used to transport materials inside cells
26
Lyosomes
Specialised vesicles that contain hydrolytic enzymes Break down waste material in cells such as old organelles Play a role in apoptosis Break down pathogens ingested by phagocytotic cells
27
Flagella
whiplike longer (than cilia) For cell movement Extensions form cell surface
28
cillia
Hair like Numerous Extensions form cell surface Present in sensory organs Involved in creating currents
29
Endoplasmic rectilium structure
flattened membrane bound sacs (cisternae) which are continuous with outer membrane
30
Endoplasmic rectilium Function
smooth= involved in making lipids rough= transport proteins made on attached ribosomes
31
Ribosomes Structure
Very small organelles in cytoplasm and on RER 2 Subunits- large and small Manufactured in the nucleolus from RNA and proteins
32
Ribosome Function
Site of protein synthesis --> Acts as an assembly line to use MRNA to make proteins
33
Golgi apparatus Structure
Stack of membrane bound flattened sacs Similar structure to the Smooth ER
34
Golgi apparatus Function
Receives proteins from ER Modifies them (post office) --> e.g. adds sugar
35
Protein production 5 key steps
1- Proteins are synthesised on ribosomes on RER 2- Pass into cisternae and are packaged into transport vesicles 3- vesicles move to golgi apparatus via function of the cytoskeleton 4-Vesicles fuse with Cis face of golgi apparatus. Proteins then enter. Proteins are structurally modified. Then leave in vesicles from the trans face 5- Secretory vesicles carry proteins to membrane and then fuse. Released via exocytosis. Some vesicles form lysosomes
36
Centrioles
small protein tubes of microtubules Form fibres in cell division called spindles which go on to separate chromosomes
37
Cytoskeleton
Present throughout cytoplasm responsible for the shape and stability of a cell holds organelles in place and controls movement
38
Cytoskeleton Microfilaments
Contractile fibres --> contain actin Responsible for cell movement
39
Cytoskeleton Microtubules
scaffolding proteins for the shape of the cell spindle fibres --> pull apart chromosomes in cell division
40
cytoskeleton intermediate fibres
mechanical strength
41
How to calibrate eyepiece graticule
SMU/ EMU x100 SMU=, stage micrometer EMU= Eyepiece micrometer
42
Graticule stage vs eyepeice
Stage= true lengths eyepiece= regular divisions that must be calibrated
43
Biological drawing low power lens
No individual cells should be drawn
44
Biological drawing 5 key points
pencil only scale bar magnification title no shading
45
Exocytosis
Process by which materials are removed from or transported out of cells ( vesicles fuse with cell membrane and release proteins)
46
Vesicle vs Pernament Vacuole
Both are membrane bound sacs that function in storage and transport Permanent vacuole doesn't fuse with membranes Plant vacuoles have enzymes that break down macromolecules --> like lysosomes
47
Compartmentalisation
The separation of the cell interior in distinct compartments with specific local conditions that allow simultaneous occurrence of diverse metabolic reactions and processes
48
Endosymbiosis
An organism that lives within the body or cells of another organism (opposite of parasitosis) Theory for ribosomes and mitochondria
49
Prokaryotes
plasmids replicate independent of main chromosomes cell wall made of peptidoglycan mesosome= inner extensions of cell membrane, site of respiration smaller ribosomes --> 70s not 80s
50
Prokaryotic ribosomes
70s not 80s s= where they settle in a centrifugal tube
51
Prokaryotic flagella
Do not have a 9+2 arrangement Smaller Movement from chemiosmosis not ATP "watermill"
52
Chloroplasts structure
2 membranes separated by a fluid filled space stack of thylakoids is a granum chlorophyll molecules present on the membranes
53
Chloroplasts Function
Site of photosynthesis Light energy is used to derive carbohydrate molecules form carbon dioxide
54
Permanent vacuole Structure
Bound by a membrane called the tonoplast Vacuole contains cell sap --> solution of sugars, amino acids, salts, waste chemicals
55
Permanent Vacuole function
Food stores accumulate waste products maintains turgidity
56
Cell wall (plants) Structure
Cellulose cell walls
57
Cell wall (plants) Function
!!!Different in bacteria and fungi protects cell from mechanical damage maintains rigidity under turgor --> water diffusion in/out of cell Freely permeable Barrier to pathogens
58
Organelles not membrane bound
Cytoskeleton villi/ flagellum ribosomes

A- Level Biology (11 decks)

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