Structure and composition

Question 1

Predominant types of molecules in a cell

Answer 1

carbohydrates, lipids, proteins and nucleic acids

Question 2

What constitutes a cell?

Answer 2

Various organelles enclosed in a membrane

Question 3

Typical sizes of cells found in body?

Answer 3

Typical cell - 25nm
nerve cell - 10cm
Muscles cells > typical cells

Question 4

What is the function of the nucleus?

Answer 4

Contains cell’s DNA

Control centre of cell

Question 5

What is the function of the nucleolus?

Answer 5

Site for ribosome synthesis

Question 6

What is the function of the nuclear envelope?

Answer 6

Separate nucleoplasm and cytoplasm

Question 7

What is the function of mitochondria?

Answer 7

ATP production

Question 8

What is the function of SER?

Answer 8

Synthesises, stores and transports lipids and carbohydrates

Question 9

What is the function of SER?

Answer 9

Produce hormones and lipids

Question 10

What is the function of ribosomes?

Answer 10

Site of protein synthesis

Question 11

What is the function of the golgi apparatus?

Answer 11

Collect, package and ditribute molecules manufactured in a cell (packaged in secretory vesicles)

Question 12

What is the function of the plasma membrane?

Answer 12

Lipid bilayer contains protein that regulate which molecules can enter and leave the cell

Question 13

What are the functions of the cytoskeletal components?

Answer 13

Support organelles and cell shape

Cell motion

Question 14

What are the functions of the cytoskeletal components?

Answer 14

Support organelles and cell shape

Cell motion

Question 15

What is the function of centrioles?

Answer 15

Spindle fibre formation

Question 16

What is the function of lysosomes?

Answer 16

Contains lysozyme for autolysis/hydrolysis

Question 17

Predominant types of molecules found dissolved in cytoplasm?

Answer 17

Soluble proteins
ions
sugars
nucleotides
amino acids
mRNA
tRNA
lipids & cholesterol
peptides

Question 18

What constitutes the ECM?

Answer 18

Basement membrane and the interstitial fluid

Question 19

What is the function of a basement membrane?

Answer 19

Surround tissue to separate lining of body surface from connective tissue

Question 20

What constitutes a basement membrane?

Answer 20

Type IV collagen network
Laminins
Type XV collagen

Question 21

What is a phosopholipid composed of?

Answer 21

polar hydrophilic head (choline phosphate and glycerol)

nonpolar hydrophobic fatty acid tails

Question 22

What is the function of interstitial fluid?

Answer 22

Bathe cells

Question 23

How is a phospholipid bilayer created?

Answer 23

It self assembles

amphiphilic phospholipids auto orient away/towards water

Question 24

Name some common phospholipids and their charges

Answer 24

Phosphatidylcholine (neutral)
Phosphatidylserine (-ve)
Sphingomyelin (contains ceramide)

Question 25

What affects bilayer packing?

Answer 25

Unsaturated fatty acids have cis double bonds | Gives a kink and therefore less tight packing

Question 26

Why is the membrane asymmetrical?

Answer 26

Neutral phospholipids tend to be on outer membrane -ve charge phosopholipids tend to be on internal side to give net -ve charge Glycolipids present on outside

Question 27

Why is the membrane asymmetrical?

Answer 27

Neutral phospholipids tend to be on outer membrane -ve charge phosopholipids tend to be on internal side to give net -ve charge Glycolipids present on outside

Question 28

What are the permeability properties of the bilayer?

Answer 28

Permeable to small neutral molecules (water, oxygen, CO2, Drugs) Impermeable to large, hydrophilic and charged molecules (Glucose, proteins, nucleic acids, macromolecules)

Question 29

What are the functions of memebrane proteins?

Answer 29

Gives cell properties Involved in signalling and movement Protein pores provide route for movement of molecules Symporters act as co-transporters Antiporters exhange molecules to regulate intracellular pH

Question 30

Define active transport

Answer 30

Active movement of molecules against concentration gradient

Question 31

Define osmosis

Answer 31

Movement of water from an area of high water potential to an area of low water potential

Question 32

Define facilitated diffusion

Answer 32

Movement of charged molecules down concentration gradient through protein channels

Question 33

How can other molecules cross the bilayer?

Answer 33

Pinocytosis - engulfment of extracellular water soluble molecules into vesicles Phagocytosis - engulfment of extacellular bacteria/debris into vesicles following their binding to cell surface receptors Exocytosis - vesicle fuses w membrane to release out of cell

Question 34

List the differences between prokaryotic and eukaryotic cells

Answer 34

Prokaryotes do not have membrane bound organelles Prokaryotes are haploid, eukaryotes are haploid or diploid Eukaryotes have a well defined cytoskeleton Prokaryotes have a peptidoglycan cell wall, eukaryotes have no cell wall