1- cell compartments and cytoskeleton

Question 1

3 domains of life

Answer 1

bacteria, archae, eukaryotes

Question 2

Prokaryotes

Answer 2

No nucleus

bacteria and archae

Question 3

Eukaryotes

Answer 3

Nucleus

Fungi, plants and animals

Question 4

Prokaryotic cells FEATURES

size,

Answer 4

Bacterial cells generally 1-5 um
Highly diverse
No distinct nucleus 
e.g. vibrio cholerae 
Plasma membrane, DNA ( loose ) ribosomes, cell wall, can have flagellum

Question 5

Bacteria - dangerous, harmless?

Answer 5

Many human diseases are caused by bacteria e.g. cholera, typhoid , samonella

Some live harmlessly in our bodies - commensalism bacteria

Others are beneficial to health e.g. gut bacteria

Question 6

Eukaryotic cells

Answer 6

10-50um or larger
Contain a nucleus and many ohter membrane bound compartments called organelles
Diverse in structure and size( even within one organism )

Question 7

cell polarity

Answer 7

Cell polarity refers to the intrinsic asymmetry observed in cells, either in their shape, structure, or organization of cellular components.

Most epithelial cells, migrating cells and developing cells require some form of cell polarity for their function

Question 8

The cytoskeleton

Answer 8

Network of protein filaments that runs throughout the cytoplasm of eukaryotic cells
3 main types
Provides structure, movement and transport inside cells

Question 9

Actin filaments

Answer 9

Can grow and shrink by adding or removing actin subunits from ends
Dynamic
Smallest
Change cell shape and cause movement
Form cellular extensions e.g. microvilli
Involved in muscle contraction

Question 10

3 proteins that make up the cytoskeleton

Answer 10

Actin filaments
Microtubules
Intermediate filaments

Question 11

Microtubules

Answer 11

Thicker than actin filaments
Hollow cylinders of tubulin subunits ( alpha and beta )
Extend from the centrosome near the nucleus
Pull apart chromosomes during cell division
Form flagella and cilia
Provide tracks fro transport of molecules or organelles using motor proteins : kinesines= outward transport and dyneins = inward transport, important in neurones with their long axons

Question 12

Intermediate filaments

Answer 12

Size between microtubules and actin filaments
Monomers twist to form rope like filaments found throughout cytoplasm
Provide mechanical strength for the cell = prevent shearing

Question 13

Nucelus

Answer 13

Double membrane called nuclear envelope
Contains DNA
Substances enter and exit via pores

Question 14

Nucleolus

Answer 14

Makes ribosomes

Question 15

Mitachondria

Answer 15

Site of ATP production during aerobic respiration

Membrane forming cristae contains enzymes used in respirationn

Question 16

SMooth endoplasmic reticulum

Answer 16

System of membranes containing fluid filled cavities( cisternae ) that are connected to the outer nuclear membrane
No ribosomes on surface
Contain enzymes that catalyse reactions involved with lipid and carbohydrate synthesis

Question 17

rough endoplasmic reticulum

Answer 17

Like the smooth ER but coated with ribosomes
Synthesis and transport of proteins
Proteins transported to golgi apparatus for modification and packaging

Question 18

Golgi apparatus

Answer 18

Looks like smooth ER but stacks like WIFI
Vesicles at the end of cisternae
Proteins are modified e.g. by being folded into 3d shape
Packaged into vesicles that are pinched off and stored in cell or moved to plasma membrane

Question 19

Cell surface membrane

Answer 19

Phospholipid bilayer with proteins and cholesterol
Barrier between cell and its surroundings, selectively permeable so controls what enters and leaves the cell
Site of cell cell recognition and recieving of cell signals

Question 20

Lysosomes

Answer 20

Specialised vesicles surrounded by a single membrane
Engulfs old cell organelles, water materials and foreign matter and return digested components to cell for reuse
Role in apoptosis

Question 21

Vesicles

Answer 21

Membranous sacks surrounded by single membrane and fluid inside
Transport materials inside the cell and have storage roles

Question 22

Ribosomes

Answer 22

Made of rRNA

Synthesising proteins

Question 23

Cytosol

Answer 23

Aqueous portion of cytoplasm

Question 24

Cytoskeleton functions

Answer 24

Organelles held in place
Controls cell movement and contraction
Organelle movement

Question 25

Peroxizome

Answer 25

Where oxidation occurs

Question 26

Centrioles

Answer 26

2 centrioles form the centrosome