chapter 5

Question 1

What is/defines the unit of a calorie?

Answer 1

amount of energ needed to raise temperature of 1 gram of water by 1 degree celcius. food Calories are larger, like a kilocalorie, so 1000 calories = 1 Calorie

Question 2

Long name for ATP

Answer 2

Adenosine triphosphate

Question 3

What is ATP made of

Answer 3

Adenosine plus a tail of 3 phosphate groups

Question 4

How does ATP work

Answer 4

Chemical energy is released by breaking down organic molecules (cellular respiration) ATP generates ATP acts like an energy shuttle, stores it, and releases it as needed is then broken down into ADP and a phosphate group, releasing energy (the other phosphate is sent to another molecule)

Question 5

Metabolism

Answer 5

the total of all chemical reactions in an organism

Question 6

Enzymes

Answer 6

proteins that speed up chemical reactions by lowering the activation energy for the reaction. enzymes are NOT used up in a reaction, can function over and over

Question 7

induced fit

Answer 7

Each enzyme recognizes a specific reactant molecule called a substrate the active site fits to the substrate, and the enzyme changes the shape slightly

Question 8

Enzyme Inhibitors

Answer 8

• Prevent metabolic reactions by binding to the active site
• bind at a remote site
• change enzyme shape
• prevent enzyme from binding to its substrate

Question 9

Feedback regulation

Answer 9

some products of a reaction may inhibit the enzyme required for its production. prevents cells from wasting resources many antibiotics work by inhibiting enzymes of disease causing bacteria

Question 10

Transport Proteins

Answer 10

proteins in membrane regulate passage of materials into and out of the cell

Question 11

Diffusion

Answer 11

Movement from high concentration to low concentration the tendency for molecules of any substance to spread out into the available space

Question 12

Passive Transport

Answer 12

The diffusion of a substance acros a membrane without input of energy

Question 13

facilitated diffusion

Answer 13

Some substances do not cross membranes spontaneously. Transported via facilitated diffusion. Specific transport proteins act as selective corridors substrate binds to the protein protein changes shape allows the diffusion of the molecule, creating a passage tunnel for large molecules and shielding from the inner membrane for polar or charged molecules. No energy input is needed

Question 14

Cells control their Chemical environment using….

Answer 14

Energy Enzymes plasma membrane

Question 15

Osmosis

Answer 15

diffusion of water across a selectively permeable membrane

Question 16

hypertonic

Answer 16

higher concentration of a solute, net movement of water is out of cell (crenates)

Question 17

hypotonic

Answer 17

lower concentration of solute, net movement is out of the cell (burst/lyses, in a plant cell called turgor pressure)

Question 18

isotonic

Answer 18

equal concentration of solute through out cell, there is NO net movement of water.

Question 19

Osmoregulation

Answer 19

the control of water balance within a cell or organism. Most animal cells require an isotonic environment to maintain morphology and tonicity

Question 20

What type of environment do plant cells require?

Answer 20

a hypotonic environment, which keeps cell wallsturgid

Question 21

What happens as a plant cell loses water?

Answer 21

-cell shrivels
-Its plasma membrane may pull away from the cell wall in the process of
plasmolysis, which usually kills the cell.

Question 22

Active transport

Answer 22

requires energy to move molecules across a membrane.

-movement is from high to low concentrations

Question 23

Exocytosis

Answer 23

the secretion of large molecules within vesicles

Question 24

Endocytosis

Answer 24

takes material into a cell within vesicles that bud

inward from the plasma membrane.

Question 25

What are the 3 types of endocytosis

Answer 25

• Phagocytosis (cellular eating):a cell engulfs a particle and packages it within a food vacuole
• Pinocytosis (cellular drinking): a cell gulps droplets of fluid by forming tiny vesicles
• Receptor-mediated: a cell takes in very specific molecules

Question 26

The plasma membrane helps convey signals between…

Answer 26

• Cells

- Cells and the environment

Question 27

signal transduction pathways

Answer 27

Triggered by receptors on a cell surface, they relay the signal and convert it to chemical forms that can function within the cell