Cell Ultrastructure

Question 1

Eukaryotic organism example’s

Answer 1

Animal and plants cells.

Question 2

Prokaryotic organism example

Answer 2

Bacteria

Question 3

What do plant cells have that animals cells do not?

Answer 3

• A Cell wall.
• A vacuole
• Chloroplasts.

Question 4

Plasma membrane

Answer 4

• Consists of phospholipids which form a bilayer.

- Regulates the movement of substances in and out of the cell.

Question 5

Cell Wall

Answer 5

• Rigid structure made of cellulose that surrounds plant cells.
• Provides support to the plant cell.

Question 6

Nucleus

Answer 6

• Surrounded by a nuclear envelope, which contains pores.
• Contains chromatin and the nucleolus.
• Controls the activity of the cell.

Question 7

Lysosome.

Answer 7

• Contains digestive enzymes which can be used to digest invading cells.

Question 8

Ribosome

Answer 8

• Found floating freely in the cytoplasm or attached to the RER.
• Site of Protein synthesis

Question 9

Rough Endoplasmic Reticulum.

Answer 9

• A system of membranes with a Surface covered with ribosomes.
• Folds and processes proteins.

Question 10

Smooth Endoplasmic Reticulum

Answer 10

• System of membranes but no ribosomes on the surface.

- Site of lipid synthesis.

Question 11

Vesicle

Answer 11

• Transports substances in and out of the cell and between organelles.
• Formed at Golgi apparatus, ER or at the plasma membrane

Question 12

Golgi Apparatus

Answer 12

• A group of flattened sacs (provides larger surface area).
• Processes and packaged new proteins.
• Makes lysosomes.

Question 13

Mitochondrion

Answer 13

• Double membrane (inner one folded to form Cristae.
• Inside is the matrix which contains enzymes involved in respiration.
• Process ATP/site of aerobic respiration.

Question 14

Chloroplast

Answer 14

• Surrounded by a double membrane.
• Thylakoids membranes inside, which are stacked up to form grana.
• Site of photosynthesis.

Question 15

Centriole

Answer 15

• Small, hollow cylinders made of microtubules.

- Involved in the separation of chromosomes during cell division.

Question 16

Cilia

Answer 16

• Ring of 9 pairs of proteins microtubules with 2 microtubules in the middle (9-2 formation).
• Move’s substances along the cell surface e.g mucus. (Allowed by microtubules)

Question 17

Flagellum

Answer 17

• Stick out from the plasma membrane.
• Microtubules contract to allow the flagellum to move.
• Flagellum help propel cells forward.

Question 18

Cytoskeleton structure

Answer 18

• Protein threads running through the cell
• Microfilaments (Very thin protein strands).
• Microtubules (tiny protein cylinders).

Question 19

Cytoskeleton function

Answer 19

• Helps the cell maintain shape.
• allows movement of vesicles.
• Allows movement of MRNA.
• Holds the organelles in position.

Question 20

Protein production

Answer 20

• Proteins are produced on the ribosomes
• Proteins which are produced on the surface on RER are folded and processed in the
  RER
• The proteins are then transported from the RER to the Golgi apparatus in vesicles
• They are then modified in the Golgi apparatus
• Golgi apparatus packages proteins into vesicles to be transported around the cells
  where they’re required.
• Some of the proteins such as extracellular enzymes leave the cell by exocytosis.

Question 21

Prokaryotic vs Eukaryotic features

Answer 21

• Small cells vs Larger cells.
• Circular DNA vs Liner DNA.
• No nucleus vs Nucleus present.
• Cell wall made of polysaccharide vs cell wall made of cellulose (plant) or chitin (fungi).