Cells & Molecular Biology

Question 1

Cell Theory

Answer 1

Something that scientists are very confident about and is well supported by all known evidence

• Theory is just below a law.

Law: is an equation that gives correct or expected outcome every time.

Question 2

Plasma (Cell) membrane

Answer 2

• Surrounds cells
• Made of proteins and lipids
• composition and function can vary from one region to another

Question 3

Cytoplasm

Answer 3

• Organelles
• Cytoskeleton
• cytosol (intracellular fluid)
• extracellular fluid- outside cells

Question 4

Phospholipids are know to be

Answer 4

Amphipathic

Question 5

Cell junctions: tight junctions

Answer 5

Tight junctions act like a seal preventing fluids to pass/leak…

Question 6

Cell junctions: Desmosomes

Answer 6

Holds cells tightly at a point like a button or an anchor and is seen in the skin

Question 7

Cell Junctions: Gap Junctions

Answer 7

Channels between cells, allows ions and small molecules to pass and are particularly important for communication in heart cells and embryonic cells

Question 8

Carrier mediated mechanism

Answer 8

Uses a membrane proteins to transport substances from one side of the membrane to the other it can be passive (no ATP) or active transport (ATP)

Question 9

What does specificity in membrane transport refer to?

Answer 9

Specific about what is allowed to pass across the membrane

Question 10

Diffusion Rates: factors affecting diffusion rate through a membrane

Answer 10

1. temperature, as it increases motion of particles increase
2. Molecular, weight large molecules move slower.
3. Steepness of concentration gradient, increasing difference increases the rate.
4. Membrane surface area when increased rate increases.
5. Membrane permeability as permeability increases rate increases.

Question 11

Osmolality

Answer 11

Measure of total concentration of solute particles

as one solution concentration goes up water concentration goes down and vice versa

**water moves by osmosis from areas of high low solute (aka high water) concentration to high areas of solute (aka low water) concentration.

Question 12

Osmosis

Answer 12

Diffusion of solvent: movement of solvent such as water across a selectively Permeable membrane

Question 13

Aquaporins(AQPs)

Answer 13

Specific water channels that are open

*flow occurs when water concentration is different on one side of the membrane than the other.

Question 14

Recap: membrane permeability to water in permeable to solutes

Answer 14

Water moves to less water/more solute side

*note more solute lower concentration of water

Question 15

Isotonic solution

Answer 15

Cells retain their normal size and shape and Isotonic solutions there is normal solute outside the cell.

Question 16

Hypertonic solution

Answer 16

Cells lose water by osmosis and shrink in a hypertonic solution

*Hypertonic means excessive solute outside the cell

Question 17

Hypotonic solutions

Answer 17

Cells take on water by osmosis until they become bloated and burst

*Hypotonic solutions have lower solute concentration outside the cells

Question 18

What would NOT be found in the plasma membrane ?

Answer 18

RNA

Question 19

Exocytosis is a?

Answer 19

Active membrane transport process.

Question 20

Cells of the body mainly use —– for the selective endocytosis of most macromolecules.

Answer 20

Receptor- mediated endocytosis

Question 21

The primary site of cellular ATP production in most cells is the…?

Answer 21

Mitochondrion

Question 22

Ribosome function?

Answer 22

Synthesize proteins

Question 23

Lysosomes function

Answer 23

Contain digestive enzymes.

Question 24

During transcription —– is used as a template to make—–

Answer 24

DNA —> RNA