2.4 eukaryotic cell structure

Question 1

the ultrastructure of eukaryotic cells and the
functions of the different cellular components

Question 1

Mitochondria structure and function

Answer 1

S: double membrane. Inner membrane is folded to form cristae. Inside the matrix is enzymes responsible for respiration
F: Site of aerobic respiration (ATP production)

Question 2

Vesicles function

Answer 2

transport material around the cell bound by a phospholipid bilayer

Question 3

Cytoskeloton function and structure

Answer 3

s: made up of
- microfilaments: contractile protein fibres formed from actin
- microtubles: globular proteins scaffold structures, “tracks” for vesivles and organelles
(spindle fibres are composed of microtubles)
-intermediate fibres:mechanical strength

F: provides structure and intracellular support

Question 4

Cytoplasm function/def

Answer 4

site of chemical reactions. composed of cytosol

Question 5

Lysosome function/def

Answer 5

Membrane-bound vesicles found in the cytoplasm that contain a hydrolytic (digestive)
enzyme called lysozyme.

Question 6

(SER) Smooth endoplasmic reticulum

Answer 6

A membrane-bound organelle involved in lipid
synthesis.

Question 7

Rough endoplasmic reticulum (RER)

Answer 7

A membrane-bound organelle that is involved in the
synthesis and packaging of proteins.

Question 8

Ribosomes def/function

Answer 8

Organelles found either free in the cytoplasm or membrane bound that are
involved in the synthesis of proteins.

Question 9

Nucleus def/function

Answer 9

An organelle found in eukaryotic cells that stores the genetic information of the cell
as chromosomes and is surrounded by a membrane called the nuclear envelope.

Question 10

Nucleolus def/function

Answer 10

Nucleolus: A structure found inside the nucleus that contains proteins and RNA
and is involved in synthesizing new ribosomes.

Question 11

Centrioles function

Answer 11

Structures found in the cytoplasm made of microtubules that produce the spindle fibres during mitosis. to organise the position of organelles. two centrioles form the centrosome

Question 12

Golgi apparatus function

Answer 12

An organelle found in eukaryotic cells that is involved in the modification
and packaging of proteins.

Question 13

Nuclear envelope

Answer 13

Nuclear envelope: A double membrane that surrounds the nucleus.

Question 14

Plasma membrane

Answer 14

A semipermeable lipid bilayer studded with proteins that surrounds the
cell and many organelles.

Question 15

Protein production overview steps 1-5

Answer 15

1. proteins are synthesised on the ribosomes bound to the ER
2. then passed into its cisternae and packaged into transport vesicles
3. vesicles transport the protein to the Golgi apparatus via the cytoskeleton
   4.fuses to the golgi where the proteins are modified, trimmed and then leave in vesicle to be excreted or used internally
4. secretory vesicle carry proteinsd that are to be released from the cell. vesicles fuse with the cell surface membrane releasing their contents by exocytosis.
   some vesicles form lysosomes these contain enzymes for use in the cells