AS - Cells and microscopy

Question 1

Light Microscopes, 
Resolution
Magnification
Advantages
Disadvantages

Answer 1

M = x1500
R = 200nm
+ Can view living organisms, Easy, cheap, small
- Limited resolution

Question 2

Transmission Electron Microscope
Resolution
Magnification
Advantages
Disadvantages

Answer 2

M = x100 000
R = 0.1nm
+ Higher resolution and magnification than LM
- Specimen cannot be alive, black and white images

Question 3

Scanning Electron Microscope
Resolution
Magnification
Advantages
Disadvantages

Answer 3

M = x500 000
R = 0.1nm
+ High magnification, can make 3D images
- Cannot be alive specimen, large, expensive

Question 4

Confocal Microscope
Resolution
Magnification
Advantages
Disadvantages

Answer 4

M = x2000
R = higher than LM, lower than EM
+ Looking at living cells
Understanding relationships between cells
Highlighting individual components of cells
- large, expensive

Question 5

Magnification Calculation

Answer 5

Image size = Magnification x Object size

(micrometres) = 1mm/1000

Question 6

Leishman’s Stain

Answer 6

Blood dried firsr, fixed with methanol, flooded left for 2 minutes than diluted with water, left 5-7 minutes, washed

Question 7

Wright’s stain

Answer 7

White Blood cell counts

Question 8

What happens if blood smear is spread to thin/thick

Answer 8

too thin: small sample

too thick: individual cells cannot be seen

Question 9

Blood Functions

Answer 9

• deliver oxygen/ nutrients to tissues
• removal of waste from tissues
• clotting
• distribution of heat to regulate core body temperature

Question 10

What are Leucocytes

Answer 10

White Blood Cells
Granulocytes - contain granules
Agranulocytes - no granules

Question 11

Neutrophils

Answer 11

Help body defend against fungal or bacterial infections
Multi lobed nucleus - allows flexibility
Engulf and breakdown bacteria

Question 12

Thrombocytes (platelets)

Answer 12

2-3(micrometer) diameter, biconcave discs
produced in bone marrow + no nucleus
blood clotting
circulate in blood for 6-7 days

Question 13

Erythrocytes

Answer 13

Deliver oxygen/ CO2
develop in bone marrow circulate i blood stream 100-120 days
Diameter = 6.2-8.2(micrometers)
2-2.5 (micrometers) thick
No nucleus, large SA/V ratio, biconcave flexible + squeeze through capillaries

Question 14

Lymphocytes

Answer 14

B: produce immunoglobulins
T: Helper T - produce cytoxins coordinate immune response.
Cytotoxic T cells: bind to antigens and destroy them

Question 15

Monocytes

Answer 15

Phagocytosis, remove dead cell debris

Question 16

Nucleus

Answer 16

Control activites of cell, genetic material, manufacture rRNA

Question 17

Mitochondria

Answer 17

1-10 (micrometers), produce ATP, energy carrier molecule, carry out later stages of aerobic respiration

Question 18

Cell Wall

Answer 18

Control what enters and exits cell

Question 19

Smooth Endoplasmic Reticulum

Answer 19

synthesise and store, transport lipids and carbohydrates

Question 20

Rough Endoplasmic Reticulum

Answer 20

Large surface area for protein synthesis + transport

Question 21

Ribosomes

Answer 21

Site of protein synthesis

Question 22

Golgi

Answer 22

Assemble polypeptide to proteins, place into vesicles

Question 23

Plant (only) organelles

Answer 23

Chloroplast: photosynthesis

Large Vacuole: Keeps cell turgid

Question 24

Prokaryotic cells

Answer 24

Circular DNA, Plasmids, mesosome, pili, flagella

Question 25

Cytoskeleton

Answer 25

``` Moves organelles through cytoplasm Microtubules: 23nm Intermediate filaments Microfilaments Maintain shape + structure of cell ```

Question 26

Protein Synthesis

Answer 26

1) Genetic info copied to Mrna 2) Mrna enters from nucleus - Cytoplasm 3) Mrna attaches to ribosome 4) Ribosome translates code into polypeptide chain 5) Protein - Vesicle - transported to Golgi 6) Golgi packages protein 7) Secreted out of cell

Question 27

Cell membranes exist...

Answer 27

around outside of ALL cells, surrounding organelles in Eukaryotic cells

Question 28

Cell membranes functions

Answer 28

Control entry and exit of molecules in organelles Provide an internal transport system Isolate organelles to allow them to carry out specific chemical reactions

Question 29

Phospholipid Bilayer

Answer 29

Disallows soluble molecules to cross membrane Allows membrane flexibility Allows membrane to be stable

Question 30

Phospholipid structure

Answer 30

Phosphate - Glycogen - 2 fatty acid tails

Question 31

Proteins

Answer 31

Intergral: within bilayer, sometimes intrinsic Peripheral: edges of bilayer, extrensic proteins

Question 32

Proteins functions

Answer 32

``` Structural support Carry soluble molecules across membrane Form channels for active transport Help cells adhere to each other Receptors for hormones, neurotransmitters ```

Question 33

Cholesterol

Answer 33

Hydrophobic - water = :( Provides strength Regulates fluidity

Question 34

Simple transport

Answer 34

Passive High concentration --> Low concentration DOWN concentration gradient Factors affecting: Concentration gradient, molecule size, surface area, diffusion distance

Question 35

Facilitated Diffusion

Answer 35

Passive | Channel/Carrier proteins

Question 36

Bulk transport

Answer 36

Endocytosis: bulk movement of material into cell Pinocytosis: Cells engulf liquid material Phagocytosis: Cells engulf solid material

Question 37

Active Transport

Answer 37

Uses carrier protein and ATP to change shape