Eukaryotic cells

Question 1

What is the structure of the nucleus?

Answer 1

• bounded by a double membrane which has numerous pores
• chromosomes + nucleolus which makes ribosomes

Question 2

What is the function of the nucleus?

Answer 2

• control centre of the cell (genetic info is stored in the nucleus)
• genes are made of the nucleic acid DNA and genes form chromosomes (chromatin)
• genes are indirectly responsible for the making of proteins.

Question 3

What is the structure of the plasma membrane?

Answer 3

• made up of a bilayer of phospholipids
• specialized proteins floating in the bilayer (for homeostasis)
• bilayer is fluid so pores are created as the phospholipids swirl about so it selectively permeable to small molecules.

Question 4

What is the function of the plasma membrane?

Answer 4

• cellular control - restricts what move in and out
• has receptor molecules which responds to chemicals like hormones
• creates compartments.

Question 5

What is the structure of endoplasmic reticulum?

Answer 5

a folded mass of membrane (made of the same phospholipids as the plasma membrane) enclosing a fluid filled space

Question 6

What is the difference between smooth and rough endoplasmic reticulum?

Answer 6

Rough = ribosomes + flatter
Smooth + no ribosomes + tubular

Question 7

What is the function of rough endoplasmic reticulum?

Answer 7

produce proteins and glycoproteins

Question 8

What is the function of smooth endoplasmic reticulum?

Answer 8

• modify proteins
• synthesise + store + transport lipids
• synthesise + store + transport carbohydrates or other substances

Question 9

What is the structure of ribosomes?

Answer 9

• made of numerous proteins and RNA
• each ribosome has 2 parts (heavy and light)

Question 10

What is the function of ribosomes?

Answer 10

Protein synthesis

Question 11

What is the structure of the golgi complex?

Answer 11

stack of membranes with smaller vacuoles or vesicles on either side of the main structure

Question 12

What is the function of the golgi complex?

Answer 12

• modifies proteins made by the endoplasmic reticulum and often adding non protein components
• exports the proteins out of the cell as needed by enclosing them in vesicles
• able to keep dangerous proteins from damaging the cell which made them by encasing them in lysosomes.

Question 13

What is the structure of a lysosome?

Answer 13

• small vesicles in the cytoplasm filled with digestive enzymes
• a membrane bound sac
• they bud off from the golgi complex and fuse with food vacuoles

Question 14

What is the function of a lysosome?

Answer 14

• has lysozymes (digestive enzymes) to digest invading cells/ assist WBCs and break down and remove old worn out cell parts
• lysozymes are kept seperate from the cytoplasm by the surrounding membrane
• involved in the digestion of food particles brought into the cell through in-foldings in the plasma membrane

Question 15

What is the structure of chloroplasts?

Answer 15

• typically form long/thin structure (short diffusion pathway)
• double membrane ~ inner membrane is highly folded into disc like structure
• each disc is a thylakoid and they forma stack (granum)
• there are many grana in each chloroplast and grana are linked by lamellae
• stroma = liquid that surrounds the thylakoid discs

Question 16

What is the function of chloroplasts?

Answer 16

• the membranes give a large surface area for the attachment of chlorophyll and other molecules needed for the 1st stage of photosynthesis
• the stroma contains all the enzymes needed to carry out the 2nd stage of photosynthesis

Question 17

What is the structure of a vacuole?

Answer 17

• membrane (called tonoplast) bound sacs of fluid/ cell sap (weak solution of salts and sugar) in the cytoplasm

Question 18

What is the function of a vacuole?

Answer 18

plants = permanent
- maintains turgor pressure in the cell by swelling with water which also pushes other organelles (particularly the chloroplasts) to the outer edges of the cell
- stops plant wilting
- involved in the isolation of unwanted chemicals in the cell

Question 19

What is the structure of the cell wall?

Answer 19

• highly rigid layer found in plant cells is composed of long strands of cellulose and other carbohydrates
• the microfibrils that forma a mesh around the cell are held in place by millions of hydrogen bonds

Question 20

What is the function of the cell wall?

Answer 20

• provide mechanical strength to prevent cell bursting due to osmosis
• allow the free passage of water through the plant

Question 21

What is the structure of mitochondria?

Answer 21

• oval (sometimes branching) and have a double membrane
• 2 compartments
  1= store hydrogen bonds which gives it electrical potential
  inner membrane = highly folded ~ rod like folds (Cristae)

Question 22

What is the function of mitochondria?

Answer 22

aerobic respiration - convert the energy in the bonds of glucose and oxygen to readily available energy in the form of ATP