cell structure.

Question 1

Plasma Membrane

Answer 1

• Description: Surface of the cell, phospholipid biolayer. Studded with glycolipids, glycoproteins and cholesterol.
• Function: Partially permeable, cell signalling, site of chemical reactions.

Question 2

Cell Wall

Answer 2

• Description: Made of; Chitin (Fungal), Cellulose (Plant) and Peptidoglycan (Bacteria) .
• Function: Gives the cell shape and support. Keeps it turgid.

Question 3

Nucleus

Answer 3

• Description: Contains the nucleolus and genetic information in the form of DNA molecules. Has a double membrane
• Function: DNA directs the synthesis of all proteins required by the cell. Controls metabolic activities of the cell.

Question 4

Nuclear Envelope

Answer 4

• Description: Contains nuclear pores. Surrounds the nucleus.
• Function: Allows molecules to move into and out of the nucleus.

Question 5

Nucleolus

Answer 5

• Description: Area within the nucleus, composed of proteins and RNA.
• Function: Responsible for producing ribosomes and combining them with proteins to form the ribosomes necessary for photosynthesis.

Question 6

Lysosome

Answer 6

• Description: Specialised forms of vesicles that contain hydrolytic enzymes. Membrane bound.
• Function: Responsible for breaking down waste material in cells, including old organelles.

Question 7

Ribosome

Answer 7

• Description: Free-floating in the cytoplasm or attached to the RER. Constructed of RNA molecules made in the nucleolus. Made of two subunits. Eukaryotic, 80s. Prokaryotic, 70s.
• Function: Site of proteinsynthesis.

Question 8

Rough Endoplasmic Reticulum (RER)

Answer 8

• Description: Has ribosomes bound to the surface. Network of flattened membrane sacs called cisternae. Membrane bound.
• Function: Responsible for the synthesis and transport of proteins.

Question 9

Smooth Endoplasmic Reticulum (SER)

Answer 9

• Description: Network of flattened membrane sacs called cisternae. Connected to the outer membrane of the nucleus. Membrane bound.
• Function: Responsible for lipid and carbohydrate synthesis, and storage.

Question 10

Vesicle

Answer 10

• Description: Membranous sacs that have storage and transport roles. Membrane bound.
• Function: Storage and transports proteins. Exocytosis. Endocytosis.

Question 11

Golgi Apparatus

Answer 11

• Description: Compact structure formed of cisternae and does not contain ribosomes. Similar in structure to the smooth endoplasmic reticulum. Membrane bound.
• Function: Modifying proteins and packaging them into vesicles.

Question 12

Mitochondrion

Answer 12

• Description: Double membrane. Inner membrane is highly folded to form structures called cristae and the fluid interior is called the matrix. Membrane forming the cristae contains enzymes used in aerobic respiration. Contain a small amount of DNA called mitochondrial mt(DNA).
• Function: Site of the final stages of cellular aerobic respiration. Production of the molecule ATP.

Question 13

Chloroplast

Answer 13

• Description: Double membrane. Fluid enclosed is called the stroma. Internal network of membranes, forming flattened sacs called thylakoids. Starch present as starch grains.
• Function: Photosynthesis.

Question 14

Centriole

Answer 14

• Description: Component of the cytoskeleton. Composed of microtubules.
• Function: Pulls the chromosomes / chromatids to opposite poles during cell division.

Question 15

Cilia

Answer 15

• Description: Extensions that protrude from some cell types. Contains two central microtubules surrounded by nine microtubules arranged like a ‘wheel’.
• Function: Move substances along the cell surface.

Question 16

Flagellum

Answer 16

• Description: Whip-like. Longer than cilia cells.
• Function: Allow movement of the cell. In some cells, detects chemical changes.