CELL STRUCTURE

Question 1

Light microscopes.

Answer 1

• R = 0.2 micrometers.
• M = x 1500.
• Light beams through dead or living specimen.
• 2D.

Question 2

Transmission electron microscope.

Answer 2

• R = 0.0002 micrometers.
• M = x 1,500,000.
• Electrons beam through dead specimen in vacuum, denser parts absorb electrons and appear darker.
• 2D, black + white.

Question 3

Scanning electron microscope.

Answer 3

• R = 0.002 micrometers.
• M = x 1,500,000.
• Electrons pass through dead specimen in vacuum.
• 3D, black + white.

Question 4

Laser confocal microscope.

Answer 4

• R = 0.2 micrometers.
• M = x 1500.
• Florescent dye on living specimen, light beam focused through pinhole onto detector.

Question 5

Eukaryotic - Animal cells.

Answer 5

• Nucleus.
• Nucleolus.
• Smooth endoplasmic reticulum.
• Rough ER.
• Mitochondrion.
• Lysosome.
• Ribosome.
• Golgi apparatus.
• Cell membrane. -

Question 6

Structure + function of nucleus.

Answer 6

• Contains genetic information in the form of chromosomes, Contains nucleolus, surrounded by nuclear envelope (double membrane) containing pores.
• Controls the cell’s activities (proteins), Synthesis of ribosomes, Substances enter or leave via nuclear pores.

Question 7

Plasma membrane.

Answer 7

• Found on the surface of animal cells, Phospholipid bilayer.
• Controls movement of cells in and out of cell (partially permeable), Cell signalling (receptors can detect signals from other cells).

Question 8

Mitochondrion.

Answer 8

• Contain enzyme-rich substance (Matrix), Surrounded by membrane (inner membrane folded to form cristae), contain own DNA, require lots of energy.
• Site of aerobic respiration (produces ATP).

Question 9

Ribosomes.

Answer 9

• Measured in S units (80s in eukaryotes), In cytoplasm or attached to the RER, Made up of proteins and rRNA, Large and small subunit, Not surrounded by membrane.
• Site of protein synthesis.

Question 10

Golgi Apparatus.

Answer 10

• Contains Golgi vesicles + cisternae (fluid filled, membrane-bound sacs).
• Processes + packages lipids + proteins into vesicles, Synthesise lysosomes.

Question 11

RER.

Answer 11

• Covered with ribosomes, network of membranes enclosing a fluid-filled space (Cisternae).
• Synthesise and transport of proteins using ribosomes.

Question 12

SER.

Answer 12

• Same as RER but no ribosomes.
• Synthesis, storage and transport of lipids and carbohydrates (e.g. cholesterol and steroid hormones).

Question 13

Lysosomes.

Answer 13

• Contain enzymes, surrounded by a membrane to enclose enzymes.
• Digest invading cells, Breaks down waste materials.

Question 14

Cytoskeleton role.

Answer 14

• Structure and support.
• Micro filaments, Microtubules, Intermediate fibres.

Question 15

Microfilaments.