Eukaryotic cell structure

Question 1

Nucleus

Answer 1

surrounded by a double membrane ( nuclear envelope)- nuclear envelope contains nuclear pores

Contains genetic information ( DNA)

Biggest single organelle in the cell

Contains histones that associate with DNA and forms chromatin

Question 2

Nucleolus

Answer 2

produces ribosomes

Composed of proteins and RNA

RNA is used to produce rRNA high is then combined with proteins to form ribosomes

Question 3

Mitochondria

Answer 3

Site of respiration

The number of mitochondria in a cell is usually a reflection of the amount of energy it uses

They have a double membrane inner membrane is folded to form cristae ( has enzymes for respiration) and fluid interior is called matrix

Have mitochondria DNA mtDNA

Question 4

Vesicles

Answer 4

membaneous sacs that have storage transport roles inside the cell.

Question 5

Lysosomes

Answer 5

specialised vesicles that contain hydrologic hydrologic enzymes. Break down waste material in cells and pathogens ingested by phagocytes and lay a role in apoptosis.

Question 6

Cytoskeleton

Has 3 components

Answer 6

network of fibres used for shape and stability of cells, hold organelles in place nd controls cell movement

Question 7

microfilaments ( component 1)

Answer 7

contractile fibres formed from actin ,cel movement and cell contraction during cytokinesis.

Question 8

Microtubules ( component 2 )

Answer 8

Globular proteins polymerase to from tubes that determines the shape of a cell

Make up spindle fibres

Question 9

Intermediate fibres

Answer 9

Give mechanical strength to cells and help maintain integrity

Question 10

Centrioles

Answer 10

component of cytoskeleton composed of microtubules

Two associated ones form centrosome which is involved in the assembly of spindle fibres

Question 11

Flagella

Answer 11

hair like extensions

Enable cell mobility
Some cells use as a sensory organ to detect external changes

Question 12

cilia

Answer 12

hair like extensions

Can be mobile or stationary

Stationary - inside of nose
Mobile - beat rhythmically acting a current for things to move e.g in trachea

Contains two central microtubules surrounded by 9 pairs of microtubules creating a wheel ( 9+2 arrangement)

Question 13

SER

Answer 13

network of membranes containing flattered cisternae

Responsible for lipid and carb synthesis and storage

Question 14

RER

Answer 14

network of membranes containing flattered cisternae

Has ribosomes bound to the surface and is responsible for the synthesis and transport of proteins

Question 15

ribosomes

Answer 15

can be free floating or attached to RER

Not - membrane bound

Made of RNA molecules

Site of protein synthesis

Mitochondria and prokaryotic cells contain ribosomes

Question 16

Golgi apparatus

Answer 16

compact structure formed of cisternae with no ribosomes

Modifies proteins and packages them into vesicles

Can be secretory or twosomes which stay in the cell

Question 17

Protein production

5 steps

Answer 17

Synthesis on the ribosomes bound to the RER

Pass into its cisternae and are packaged into transport vesicles

Vesicles containing the proteins move towards the Golgi apparatus via the cytoskeleton

The vesicles fuse with the cis face of the Gogi apparatus and the proteins enter. The proteins are structurally modified before leaving the Golgi apparatus in vesicles from its trans face

Secretory vesicles carry proteins that are supposed to be released from the cell

The vesicles move towards and fuse with the cell surface membrane releasing the proteins by exocytosis

Some vehicles form lysosomes these contain enzymes for use in the cell