Studying Cells

Question 1

Eukaryotic cell definition

Answer 1

Cells that have a true nucleus and membrane bound organelles such as plant, animal , protists and fungi

Question 2

Structure and function of nucleus

Answer 2

Structure= double membrane, chromatin which is DNA associated with histone, nuclear envelope, nuclear pores, nucleulous
Function= stories genetic material for production of polypeptide chain, site of DNA replication, site of mRNA, tRNA, rRNA production

Question 3

Structure and function of mitochondria

Answer 3

Structure= double membrane, outer and inner membrane. Highly folded sacks to form crista. Liquid matrix which contains its own 70s ribosomes and DNA
Function= site of ATP production by aerobic respiration

Question 4

Structure and function of ribosomes

Answer 4

Structure= made of 2 Subunits made of rRNA and ribosomal protien
Function= site of protein synthesis

Question 5

Structure and function of rough endoplasmic reticulum

Answer 5

Structure = highly folded flattened sacks called cisternea with 80s ribosomes embedded within
Function= synthesis and transport of proteins throughout the cell

Question 6

Structure and function of smooth endoplasmic reticulum

Answer 6

Structure = highly filed membrane into flattened sacks called cisternea with no ribosomes embedded in membrane
Function = recombines fatty acids and glycerol into Triglycerides and packages into vesicles to be transported to golgi

Question 7

Structure and function of golgi body

Answer 7

Strcture = Flattened sacks filled with fluid and golgi vesicles pinch of main membrane
Function= sort modify and package protiens into vesicles

Question 8

Structure and function of lysozyme

Answer 8

Structure = membrane bound organelle that contains hydrolctic enzymes
Function = digest pathogens

Question 9

Structure and function of cell surface membrane

Answer 9

Structure = made of phospholipids, protiens , carbohydrates forming a fluid mosaic model
Function = control what molecules come in and out the cell

Question 10

Structure and function of centrioles

Answer 10

Structure = microtubules
Function = form spindle fibres which attach to centromere of chromosomes and pull apart in anaphase during mitosis

Question 11

Structure and function of chloroplasts

Answer 11

Structure = granum which are stacks of thylokoid membrane, thylokoid membrane which contain chlorophyll and ATP synthsase, stroma= fluid filled part where photosynthetic reaction occur, starch grains which are a energy storage molecule in plants, double membrane and 70s ribosomes and its own DNA
Function = site of Photosynthesis

Question 12

What is fungi cell wall made from?

Answer 12

Chitin

Question 13

Animal vs plant cell

Answer 13

Carbohydrates stored as glycogen vs carbohydrates stored as starch
Centrioles vs no Centrioles
No cell wall vs cell wall
No vacuole vs vacuole
No chloroplasts vs chloroplasts

Question 14

Prokaryotic cell definition

Answer 14

Cell that has no true nucleus and no membrane bound organelles.

Question 15

Bacteria cell structure

Answer 15

Mesosome instead of mitochondria
Capsule
Flagella
70s ribosomes
Circular DNA not associated with histones and is free in nucleus
Plasmids
Cell wall made from peptiglycogen or muerin
Cell membrane

Question 16

Prokaryotic vs eukaryotic cell

Answer 16

DNA is circular and not associated with histone vs DNA is linear and is associated with histone
DNA is free in cytoplasm vs DNA is enclosed in nucleus
Cell wall made of muerin or peptiglygen vs cell wall made of cellulose
70s ribosomes vs 80s ribosomes
Mesosome vs mitochondria
Capsule and flagella vs none of these
No true nucleus and no membrane bound organelles vs membrane bound orgalles and true nucleus

Question 17

Viruses

Answer 17

They are acceluar which means they aren’t made out of cells and don’t respire

Question 18

Features of TEM

Answer 18

High resolution due to short wavelengths of light
Sample has to thin in order for electrons to trasmit through the sample. Can see internal structures. More darker parts shows denser organelles

Question 19

Features of SEM

Answer 19

Electrons bounce of the surface of the specimen and can see 3D structure

Question 20

Describe how you would make a temporary mount when using a light microscope?

Answer 20

1. Add a drop of water to microscope slide
2. Get a thin piece of sample and place of water
3. Stain with KI solution
4. Lower cover slip woth mounted needle to avoid air bubbles

Question 21

Describe how the student could have used an eyepiece gratiticule to determine the mean diameter?

Answer 21

Measure each thing with eye piece graticule
Calibrate against a stage micrometer
Take at least five measurements and calculate a mean

Question 22

Equation for magnification

Answer 22

I = AM

Question 23

Units

Answer 23

1m = 1000mm
1mm= 1000 um
1um = 1000 nm

Question 24

Cell fractionation and differential centrifuge

Answer 24

Tissue is homogenised in a blender to break open cells releasing organelles into a solution which is ice cold to reduce enzyme activity, buffered to keep PH constant to no denature of protiens and isotonic to prevent lysis and strinking
Filter to remove any large debris
Differential centrifuge at a high speed to release dense organelles into pellet from supernatant and then centrige at a higher speed for a longer time to release next densest organelles into pellet with her is the mitochondria or chloroplasts
Repeat until organelles are separated according to their densities

Question 25

Light vs electron microscope

Answer 25

Low resolution and magnification due to long wavelengths of light vs high resolution due to short wavelengths of electrons Sample can be alive vs sample has to be in a vacuum Focused by lens vs Focused by electromagnets Easy to dye vs difficult staining method No artefacts presents vs artefacts present