cellular function

Question 1

a. Outline basic principles of structure and function of membranes

Answer 1

Function- form a barrier around cell and cell compartments, control chemical environment, recognition and communication

structure made of a phospholipid bilayer - head polar and hydrophilic and tail is hydrophobic = amphipathic

spontaneously form I layer with tails facing in

Question 2

name the cell compartments

Answer 2

cytosol (gray), endoplasmic reticulum, Golgi apparatus, nucleus, mitochondrion, endosome, lysosome, and peroxisome

Question 3

function of nucleus

Answer 3

Stores hereditary material and coordinates growth, metabolism and protein synthesis

Question 4

function of mitochondria

Answer 4

Generating + transforming the energy –vital in metabolisms like oxidative phosphorylation

Question 5

function of Endoplasmic reticulum

Answer 5

Storage + secretion of proteins and lipid

Question 6

function of Golgi

Answer 6

Modifies proteins and packages them into vesicles

Question 7

function of Golgi

Answer 7

Modifies proteins and packages them into vesicles

Question 8

function of endoscopes and lysosomes

Answer 8

Stores digestive enzymes Transports materials from the Golgi to the lysosome

Question 9

Describe behaviour of cell compartments and their interrelationships: secretion and intake

Answer 9

Some proteins are made on ribosomes that are free in the cytoplasm.
▪ From there some proteins move into the nucleus while others are directed into
mitochondria. Proteins destined to RER have a signal peptide telling them where to go
▪ Signal peptide binds to ER. Rest of protein is translated. Membrane proteins and proteins to be secreted are produced by ribosomes on the endoplasmic reticulum (ER). This organelle produces, processes, and ships out both proteins and lipids.

Question 10

c. roles of the cytoskeleton: microtubules, Myosin and Actin, microtubule associated proteins

Answer 10

-The actin cytoskeleton provides thrusting and contractile forces,

• microtubules form a
  polarized network allowing organelle and protein movement throughout the cell.
• Intermediate filaments are
  generally the most rigid component = maintenance of the overall cell shape.

Question 11

smooth vs rough ER function

Answer 11

SMOOTH ER – small, interconnected tubules. It functions in the biosynthesis of lipids, phospholipids, and cholesterol for steroid (in the liver - cytochrome P450 for detox of drugs and alcohol; in muscle the SER is termed the sarcoplasmic reticulum and stores and releases Ca2+ ion for muscle contraction).

ROUGH ER - broad flat cisternae studded with ribosomes - major role in protein synthesis.

The two types interconnect and both are connected to the nuclear envelope

Question 12

elationship between

endosomes, lysosomes and Golgi and their functions

Answer 12

Endosomes receive materials taken into the cell through endocytosis into vesicles. The endosomes sort and recycle membrane components to the cell surface and send the rest on to the lysosomal system, where they are joined by Golgi vesicles containing enzymes that break down the vesicle contents into fundamental component that can be reused by the cell.
Phagocytosis is similar but a number of things can occur after/during. The cell could present some part of the material on its cell surface- antigen presentation.