LO 3.1-3.2 Cellular level of organization & Protein Synthesis

Question 1

How many cells are in the human body?

Answer 1

100 trillion cells

200 types, and they vary in size

Question 2

Define: Cell

Answer 2

Basic, living, structural and functional unit of the body

Question 3

Define: Plasma Membrane

Answer 3

• Separates the internal part of the cell from the outside environment
• Regulates what enters and leaves the cell
• Also called the fluid mosaic model
• Composed of a phospholipid bilayer

Question 4

Define: Cytoplasm

Answer 4

Everything in the cell between the membrane and the nucleus

- contains cytosol and organelles

Question 5

Define: Nucleus

Answer 5

• largest organelle

- contains most of the cell’s DNA

Question 6

What is found within the phospholipid bilayer?

Answer 6

1) Cholesterol
2) Integral proteins
3) Peripheral proteins
4) Carbohydrates

Question 7

Define: Cholesterol in the phospholipid bilayer

Answer 7

• Found on both sides of the phospholipid bilayer

- Adds a bit of stiffness to the membrane

Question 8

Define: Integral proteins in the phospholipid bilayer

Answer 8

• “Channel proteins”
• Inserted in lipid bilayer, extending through the entire bilayer
• Allow passage of non-lipid soluble materials in and out of cell

Question 9

Define: Peripheral proteins in the phospholipid bilayer

Answer 9

• Loosely attached to inner and outer surface of membrane
• Some are enzymes required for movement of materials
• Cytoskeleton of cytoplasm anchored to these proteins helps maintain shape of cell

Question 10

Define: Carbohydrates in the phospholipid bilayer

Answer 10

• Provide recognition sites for cell interactions
• Attached to the outer surface of some lipid molecules (glycolipids)
• Attached to the outer surface of some integral proteins (glycoproteins)
• identifies cells the same to yours for organ transplants

Question 11

Which factors affect the passage of materials?

Answer 11

Lipid Solubility, Size, Charge, Channels and Carriers

Question 12

Define: Lipid solubility

Answer 12

• Most of the membrane is lipid and hydrophobic
• Lipids pass freely through the membrane
• Polar material (water, salts, acids, etc.) do NOT pass

Question 13

Define: Size

Answer 13

Small molecules generally cross more readily than large molecules

Question 14

Define: Charge

Answer 14

Charges on the membrane attracts ions of opposite charge, then move them through the protein channels

Question 15

Define: Channels and Carriers

Answer 15

• Channels in integral proteins facilitate passage of charged and polar molecules
• Carrier molecules carry large molecules through protein channels

Question 16

Define: Passive transport

Answer 16

• does not use energy from the cell, uses only kinetic energy of molecules involved

Question 17

Define: Concentration gradient

Answer 17

• Molecules move from HIGH to LOW concentration.. Down the concentration gradient

Question 18

How does passive transport move along the concentration gradient?

Answer 18

In passive transport, molecules tend to move from an area of high concentration to an area of lower concentration

Question 19

Passive Transport:

Simple diffusion

Answer 19

• Takes place through the phospholipid bilayer or without a membrane as with sodium chloride in water

Question 20

Passive Transport:

Facilitated Diffusion

Answer 20

• Accomplished with the assistance of an integral membrane protein that serves as a carrier or transporter
• Allows lipid insoluble and large molecules such as amino acids and CHOs to enter and exit the cell
• No energy needed
• Moves down the concentration gradient (high to low)

Question 21

Facilitated diffusion allows molecules to move faster then by simple diffusion. What is this rate affected by?

Answer 21

• Concentration gradient
• Amount of carrier protein available
• How quickly the molecule attaches to the carrier

Question 22

Passive Transport:

Osmosis

Answer 22

Movement of water across a selectively permeable membrane to an area where there are more water molecules to an area with less water molecules

• No energy needed
• Moves from high to low H2O concentration

Question 23

Passive Transport:

Isotonic solution

Answer 23

When the water and solute concentration of intracellular and extracellular fluid is identical

• Water movement into the cell equals movement of water out of the cell
• Isotonic solution of saline for RBC = 0.85%

Question 24

Passive Transport:

Hypotonic Solution

Answer 24

Hypotonic = When a cell is placed in a solution having a lower concentration of solute than found inside the cell

• Water will move inside the cell
• Cell will swell and burst
• In a RBC this is called hemolysis

Question 25

Passive Transport:

Hypertonic Solution

Answer 25

Hypertonic= When a cell is placed in a solution with a higher concentration of solute than that found inside the cell

• Water will move out of the cell
• Cell will shrink
• In a RBC this is called crenation

Question 26

Passive Transport:

Filtration

Answer 26

The movement is from an area of high hydrostatic (fluid) pressure to an area of low pressure

• Small molecules move across the membrane, but large molecules do not
• Pressure involved is blood pressure

Question 27

Define: Active Transport

Answer 27

Requires input of energy from the cell

- ATP to ADP releasing energy

Question 28

When do we use Active transport?

Answer 28

• When molecules are too big
• When molecules are repelled by the same charge
• Ions are being moved against the concentration gradient (low to high) by Sodium-Potassium Pumps