Biology Unit 3 Section 1 + 2 Test Studyguide

Metabolism

Metabolism

All of the chemical reactions within each cell of an organism (provide energy for life’s processes; create key molecules)

Chemical reactions

the breaking and forming of bonds between different substances during chemical changes

Breaking a bond

requires energy to be absorbed; endothermic

Creating a bond

releases energy; exothermic

Catabolic

breaks down larger molecules into simpler compounds; a release of energy

Exergonic

a release of energy

Anabolic

builds larger molecules from smaller ones; requires consuming energy to do it

Endergonic

requires consuming energy to do it

Reactants

(substrate): substances that are CHANGED during a chemical reaction

Products

Substances that are MADE by a chemical reaction

Endothermic

absorbs energy

Photosynthesis

EX of endothermic reactions

Exothermic

releases energy

Cellular respiration

EX of exothermic reactions

Light energy is STORED as chemical energy in SUGAR

Photosynthesis

Chemical energy in sugar is converted to chemical energy RELEASED as ATP

Cellular respiration

Enzymes

mostly proteins that speed up biochemical reactions by lowering the activation energy

Catalysts

(enzymes) are substances that speed up reactions without being permanently altered (Lower activation energy)

very specialized molecules that bind to reactants; help to break or form bonds, releasing a newly created product; an active site that fits only one substrate (induced fit)

What are enzymes?

Can be used over and over again

What is a special quality of enzymes?

Enzymes can break bonds in a substrate to form two products or can make bonds between substrates to form one product

What can enzymes do?

Denaturation

Enzyme’s active site gets deformed and loses its specific shape —> loss of biological activity

Temperature

increasing temperature increases the rate of the reaction

pH

how acidic or basic a solution is (Most enzymes only work at a very specific pH so if the pH changes, it can affect the speed of reaction/cause denaturation)

Substrate Concentration

the higher the amount of substrate, the faster the reaction (more particle collisions)

Co-enzymes

helper enzymes that speed up reactions

Competitive Inhibitor

slows down the reaction; and competes with the substrate for the active site on the enzyme

ATP

Adenosine Triphosphate: An energy-carrying molecule that carries/stores energy for cell functions

Adenine

Nitrogen base

Ribose

Sugar ring

Phosphate

an anion, salt; 3 groups in ATP, 2 groups in ADP

Adenine (green), Ribose (blue), Phosphate (red)

Label ATP structure

NOT a stable molecule (easy to break the bonds between the second and third phosphate groups)

Why can the third phosphate group break easily?

ADP

Adenosine di-phosphate (2 phosphates); used to create ATP (recycled)

ADP and a phosphate group combine together using energy from broken down food to create ATP. ATP breaks its bond with the third phosphate group and the energy released goes to other cell processes and becomes ADP and a phosphate group.

Process of making ADP to ATP

Exothermic reaction (breaking bonds)

ATP to ADP

Endothermic reaction (creating bonds)

ADP to ATP

Carbohydrates (commonly broken down for ATP), Lipids/fats (broken down after carbs), proteins (least likely to be broken down)

Where does energy come from?