2.1.1 Structure of Eukaryotic Cells

Question 1

Definition Endoplasmic reticulum

Answer 1

System of sheet like membranes

Question 2

RER

Answer 2

Attached to nucleus
Ribosomes on surface
Large SA for protein synthesis
Pathway to transport proteins out of cells
Produce gylcoproteins

Question 3

SER

Answer 3

Found throughout cytoplasm
No ribosomes
Synthesises, stores and transports lipids and carbohydrates

Question 4

Definition of Golgi apparatus

Answer 4

Flattened stacks of membranes with rounded structures called vesicles

Question 5

Golgi apparatus function

Answer 5

Proteins and lipids are modified by adding a non-protein component
These are then transported in vesicles that fuse with the cell surface membrane to release its contents
Forms lysosomes

Question 6

Lysosomes

Answer 6

No clear internal structure
Formed from GA
Contains enzymes called lysozymes
Isolates harmful enzymes
Breaks down material ingested by phagocytic cells 
Releases enzymes to outside of cell
Digests worn out organelles

Question 7

The nucleus

Answer 7

Nuclear envelope - double membrane controls material entry and exit

Nuclear pores - allows large molecules out of the nucleus such as ribosomes

Nucleolus - makes ribosomes

Chromatin - controls cell activity - made of DNA and protein

Question 8

Ribosome

Answer 8

Found in cytoplasm or RER

Used for protein synthesis

80s type in eukaryotic cells
70s type in prokaryotic cells

Question 9

Microvilli

Answer 9

High surface area for absorption

Finger like projections of epithelial cells

Question 10

Mitochondria

Answer 10

Double membrane - envelope

Inner membrane folded - called cristae which increases SA. Also contains enzymes ATP synthase for respiration

The matrix (fluid medium) contains:
Enzymes for respiration
Genetic material for mitochondrion reproduction
Ribosomes, sugars and proteins

Size increases long and thin so there is a shorter diffusion pathway and to increase SA

Question 11

Chloroplast

Answer 11

Envelop
Thylakoid - folded membrane - increased SA for light absorption
Stack of thylakoids is a granum

Starch grain - glucose storage
Lipid droplet - carbs stored as lipids

Stroma - medium where light independent stage occurs
DNA and ribosomes

Question 12

Vacuole

Answer 12

Cell sap - contains mineral salts for water movement
Amino acids and sugar for energy storage
Pigments (anthocyarins) for the colour of the petals

Pushes cytoplasm and surrounding membrane outwards to make it turgid

Question 13

Cell wall

Answer 13

Gives cell mechanical strength at a cellular level and for the whole plant
Contains a matrix of cellulose chains
The hydrogen bonds - microfibrils - give the cell wall mechanical strength
Cell walls allow the movement of water
Middle lamella - boundary between cells - cements them together

Question 14

Structure of prokaryotic cell

Answer 14

No true nucleus - circular DNA floats free in cytoplasm
Cell wall is made of gylcoproteins called murein - 10-80nm thick
Have a mucilaginous slime capsule for protection from immune system
Circular DNA called Plasmids - genetic info for antibiotic resistance
Bacterial chlorophyll
Flagellum - for movement