The eukaryotic cell

Question 1

What is a plasma membrane

Answer 1

A continuous double membrane called a phospholipid bilayer. Fluid so proteins can move through it

Question 2

Phospholipids in plasma membrane

Answer 2

Hydrophilic head and hydrophobic tail, not soluble in water so allows for compart mentalism. Saturated tails have no double bond and are straight. Unsaturated have a double bond and a kink in their tail. If more tails are saturated they can pack closely together.

Question 3

Cholesterol in plasma membrane

Answer 3

Sit in between the phospholipids, have a stiffened and fluid region.

Question 4

Substances on the plasma membrane which effect its function

Answer 4

Transporters- move ions across cell membrane
Anchors- attach cell to extracellular matrix
Receptors- receive messages
Enzymes- catalyse reactions within the cell

Question 5

Location of proteins in the plasma membrane

Answer 5

Integral- inside the membrane partially, transmembrane proteins cross the whole membrane
Peripheral- attached to integral protein or lipid anchored

Question 6

Carbohydrates in plasma membrane

Answer 6

Attached to lipids (glycolipids) or proteins (glycoproteins). They provide a distinct pattern on the cell allowing for cell to cell recognition. They also provide protection for the membrane

Question 7

Plasma membrane function

Answer 7

1) Physical isolation- allows separation so you can control the conditions of the cell compared to outside.
2) Regulation of exchange with environment- forms a selectively permeable barrier, proteins allow entry of specific substances.
3) Communication between the cell and its environment via receptors.
4) Structural support- anchors cell to extracellular matrix

Question 8

Cilia

Answer 8

Finger like projections which increase the surface area of the cell, i.e. in the gut

Question 9

Nucleus

Answer 9

Contains DNA, site of transcription to produce RNA which leaves the nucleus as mRNA

Question 10

Rough endoplasmic reticulum (RER)

Answer 10

Ribosomes bound to the surface of the ER, involved in the synthesis of membranes and secreted proteins

Question 11

Smooth endoplasmic reticulum (SER)

Answer 11

Stacked compartments, no ribosomes attached, synthesises lipids

Question 12

Ribosomes

Answer 12

Made of RNA and proteins, translates mRNA to proteins, Can be either attached to the endoplasmic reticulum or free floating

Question 13

Cytosol

Answer 13

Inside space within the cell excluding organelles

Question 14

Golgi apparatus

Answer 14

Stacked compartments, modification of proteins

Question 15

Mitochondria

Answer 15

Energy source of cell, produces ATP

Question 16

Lysosome

Answer 16

Breaks down macromolecules

Question 17

Endosome

Answer 17

Breaks down internalised proteins

Question 18

Peroxisome

Answer 18

Oxidises organic molecules

Question 19

Cytoskeleton

Answer 19

Provides structure, helps move molecules within the cell

Question 20

Adhesion proteins

Answer 20

attaches the cytoskeleton to cell membranes

Question 21

Definition of Eukaryotic cell

Answer 21

Have a distinct nucleus and membrane bound organelle. Animal, plant and fungi