organelles and the cell membrane

Question 1

what are the main organelles in a eukaryotic cell

(5)

Answer 1

nucleus, nucleolus, ribosomes, mitochondria, chloroplasts,

Question 2

nucleus

Answer 2

contains and protects the DNA of a eukaryotic cell

Question 3

nucleolus

Answer 3

creates subunits of ribosomes assembled from protein and RNA

Question 4

ribosomes

Answer 4

assembles polypeptide chains that are used to form proteins

Question 5

mitochondria

Answer 5

Specializes in making ATP during aerobic
cellular respiration

Question 6

chloroplasts

Answer 6

Provides cell structure, helps with cell division and allows for the movement among organelles within the cell

It has enzymes and pigments to perform photosynthesis

Question 7

why is the cell membrane based on the fluid mosaic model?

Answer 7

It is a biological membrane consisting of a
fluid phospholipid bilayer in which proteins
are embedded and float freely

Question 8

Why is the cell membrane asymmetrical?

(2)

Answer 8

• Membranes are asymmetrical, the components on one side of the bilayer, differ from the other side.
• Each half of the membrane performs different functions because different things are happening inside vs. outside the cell.

Question 9

glycolipid

Answer 9

membrane lipid bound to a carbohydrate
it is located on a lipid in the phospholipid bilayer

Question 10

glycoprotein

Answer 10

membrane component that contains a sugar (or carbohydrate) and is bound to an amino acid is located on the transmembrane proteins

Question 11

the main molecules forming the structure of the cell membrane

Answer 11

phospholipids

Question 12

what molecules are embedded in the membrane

Answer 12

cholesterol

Question 13

what influences fluidity of a cell membrane

(3)

Answer 13

temperature, composition of lipid molecule (saturated vs. unsaturated) and sterols

Question 14

discuss the role of cholesterol at high/low temperatures)

(2)

Answer 14

At high temperatures – they restrain the
movement of lipid molecules, thus reducing
the fluidity of the membrane

At low temperatures – they occupy the spaces between the lipid molecules preventing them from associating and forming a semi-solid gel

Question 15

What are the four functional categories of membrane proteins

Answer 15

transport, enzyme activity, triggering signals, attachment & recognition

Question 16

integral proteins

Answer 16

Embedded in the lipid bilayer interacting with hydrophobic core

Question 17

peripheral proteins

Answer 17

On the surface of the membrane and don’t interact with the hydrophobic core.

Question 18

transmembrane proteins

Answer 18

span the entire plasma membrane. Transmembrane proteins are found in all types of biological membranes.