Eukaryotes & Prokaryotes

Question 1

Function of the nucleus

Answer 1

• site of dna replication + transcription (making mrna)
• contains the genetic code for each cell
• site of ribosome synthesis

Question 2

Nucleus structure

Answer 2

Nuclear envelope = double membrane
Nuclear pores - holes to let mRNA etc out
Nucleolus - smaller sphere inside which = site of rna production + makes ribosomes
- nucleoplasm = site of granular, jelly like material

Question 3

What’s the flagella

Answer 3

A whip like structure for mobility & sometimes as a sensory organelle for chemical stimuli

Question 4

What are cilia + features

Answer 4

Hairlike projections that come out of cells
- they can be mobile or stationary
Mobile = help move substances in a sweep motion e.g. mucus in trachea
Stationary - key in sensory organs e.g. nose

Question 5

What are centrioles

Answer 5

• made up of microtubules
• occur in pairs to form a centrosome

Question 6

What are centrioles involved in

Answer 6

Production of spindle fibres, flagella, undulipodia
Organise chromosomes in cell division

Question 7

What is the cytoskeleton

Answer 7

A network of protein fibres running through the cytoplasm: consisting of,
Microtubules
Microfilamnets
& intermediate filaments

Question 8

What are microtubules

Answer 8

(Found on cytoskeleton interior)
Maintain cell shape by resisting compressive forces and acts as tracks for movement of organelles

Question 9

What are microfilaments

Answer 9

(Thickening the cortex) they resist tension & are responsible for cell movements & contraction

Question 10

What are intermediate filaments/fibres

Answer 10

Found throughout cell
Hold organelles & provide mechanical strength

Question 11

Function of the cytoskeleton
ALL REQUIRE ATP

Answer 11

• move chromosomes
• move organelles
• change cell shape in processes like cytokineses & endocytosis
• move cilia & flagella
• support the cell and maintain its shape

Question 12

Rough endoplasmic reticulum and smooth endoplasic reticulum differences & similarities

Answer 12

• sim: both have folded membranes called cisternae
• diff: RER = ribosomes on the CISTERNAE too + PROTEIN synthesis
  SER = no ribosomes & synthesis & storage of LIPIDS & CARBOHYDRATES

Question 13

What’s the Golgi apparatus & vesicles

Answer 13

Where protein are modified & packaged off into
Vesicles (folded membranes making cisternae, tho secretary ones pinch off from the cisternae)

Question 14

Function of the Golgi apparatus & the vesicles

Answer 14

Add carbohydrates to proteins to form glycoproteins
Produce secretory enzymes
Form lysosomes
Transport modify & store lipids

Finished products are transported to cell surface in Golgi vesicles where they fuse with the membrane and the contents are released

Question 15

What are lysosomes

Answer 15

Bags of hydrolytic digestive enzymes (50 diff types)

Question 16

What do lysosomes do

Answer 16

• hydrolyse phagocytic cells
• completely break down dead cells (autolysis)
• exocytosis (release enzymes to outside the cell to destroy material)
• digest worn out organelles for reuse of materials + break down pathogens

Question 17

Mitochondria structure

Answer 17

• double membrane (Cristae inner membrane)
• mitochondrial matrix (fluid centre)
• loop of mitochondrial dna

Question 18

Function of mitrochindra

Answer 18

Site of atp production & aerobic respiration
Dna there to code for enzymes needed in respiration

Question 19

Ribosome function

Answer 19

Site of protein synthesis

Question 20

Ribosome structure details

Answer 20

80s = large ribosomes in Eukaryotic cells
70s in prokaryotic cells / mitochondria / chloroplasts
They’re small and made up of 2 subunits of protein & rRNA

Question 21

Chloroplast function

Answer 21

Site of photosynthesis

Question 22

Chloroplast structure

Answer 22

Surrounded by double membrane
Found in plants
Fluid filled stroma contains enzymes for photosynthesis
Contains thylakoids (folded membranes with pigment)

Question 23

Cell wall function

Answer 23

Provide structural strength to cells (plant & fungi)

Question 24

Cell wall structure (plants vs fungi)

Answer 24

Plant cells = made up of microfibrils of the cellulose polymer
Fungi = made of chitin (nitrogen containing polysaccharide)

Question 25

Cytoplasm function

Answer 25

Where metabolic reactions occur

Question 26

Cell surface plasma membrane function and structure (short)

Answer 26

Phospholipid bilayer
Controls what exits & enters cell
Found in all cells

Question 27

Production & secretion of proteins steps

Answer 27

1. Polypeptide chains are synthesised on the RER
2. These chains move to the cisternae in the RER and are packaged into vesicles to be sent to the Golgi apparatus via the cytoskeleton
3. In the Golgi apparatus, proteins modified & packaged into the vesicles
4. Secretory vesicles carry the proteins to the cell surface membrane where it fuses & releases the protein by exocytosis

Question 28

What ribosomes make want proteins (e.g. intracellular vs extracellular proteins)

Answer 28

Free ribosomes = intracellular
Ribosomes in the RER = extracellular (2 be secreted by cell!)

Question 29

Vacuole function

Answer 29

Maintains the turgidity of the cell
Contains selectively permeable tonoplast containing cell sap

Question 30

How do prokaryotic cells differ from eukaryotic cells

Answer 30

• no nucleus or nuclear envelope
• 70s ribosomes
• no RER, vesicles, Golgi apparatus
• peptidoglycan cell wall
• reproduce via binary fission
• DNA not in nucleus / wound around histone proteins

Question 31

How eukaryotic and prokaryotic cells are similar

Answer 31

Both have ribosomes and cytoplasms

Question 32

Before protein synthesis what happens flow chart

Answer 32

Nucleus contains gene for protein
Protein transcribed in nucleus
MRNA produced
MRNA leaves nucleus through nuclear pores
Protein syntehssi (translation occurs at the RER)