(Bio) Unit 3

In enzymes, kinetic energy is stored in the

bonds

A reaction starts with a ________ and ends with a _________.

substrate, product

Energy of activation

the amount of energy required to start a reaction

Enzyme

A type of (usually) protein that speeds up a chemical reaction in a living thing

enzymes are

organic catalysts

Characteristics of catalysts

speed up reactions by lowering activation energy, only work in one specific reaction, reusable

Substrate

A specific reactant acted upon by an enzyme

Active site

The part of an enzyme where the chemical reaction occurs.

induced fit model

enzyme model where the substrate induces the enzyme to alter its shape slightly so it fits better

Enzyme-substrate complex

A temporary complex formed when an enzyme binds to its substrate molecule(s).

After chemical reaction, substrate(s) turn to

Product(s)

Factors that can affect enzymes

temperature, pH, and enzyme concentration

Cold temperatures will make reactions

slower

Warm temperatures will make reactions

faster

If an enzyme gets too hot

it will denature

Denaturation

loss of normal shape of a protein due to heat or other factor

If an enzyme is exposed to pH levels that are too acidic or too basic

it will denature

The more enzyme in a reaction

the faster the reaction proceeds

The less enzyme in a reaction

the slower the reaction proceeds

the more substrate in a reaction

the slower the reaction proceeds with more product

The less substrate in a concentration

the faster the reaction proceeds with less product

Inhibitors

stop or slow the enzyme's functioning

Competitive inhibitors

Compete with the substrate to slow the enzyme's ability to function

Noncompetitive inhibitors

Bond with the enzyme and stop is functioning, potentially causing permanent damage to the enzyme

Examples of noncompetitive inhibitors

toxins and poisons

Negative feedback

When the body uses competitive inhibitors to regulate itself

Cofactors

inorganic enzyme helpers (ions and minerals)

Coenzymes

organic enzyme helpers (vitamins)

Exergonic reaction

when a reaction releases energy

Endergonic reaction

when a reaction takes in more energy than it releases (stores)

Electronegativity

tendency of atoms to want to take electrons from other atoms

Redox reactions

When there is a transfer of one or more electrons from one reactant to another (oxidation and reduction)

Oxidation

when an atom loses an electron during a reaction

Reduction

when an atom gains an electron during a reaction

Biochemical pathway

a series of linked reactions

Metabolism

the sum of the reactions in a biochemical pathway

Homeostasis

when a cell regulates its chemical reactions/maintains internal equilibrium

ATP (adenosine triphosphate)

transports energy needed for metabolic reactions around the cell

ATP is a

nucleotide, with ribose as its sugar and adenine as its nitrogenous base

ATP has ___ phosphate groups

three

ADP (adenosine diphosphate)

the outcome of ATP after the energy within is used

ATP has ___ and ADP has ___

energy, no energy

Photosynthesis uses the energy of what to make sugar

Sunlight

Autotrophs

organisms that preform photosynthesis

Photons

particles of light that move in waves

Sunlight is

visible/white light

Pigments

capture most of the plant's energy

Chlorophyll

Most common pigment, absorbs all colors except green

Chlorophyll A

Primary pigment, absorbs more red

Chlorophyll B

Accessory pigment, absorbs more blue

Carotenoids

absorb more blue and reflect orange

Formula for photosynthesis

6H₂O + 6CO₂ → C₆H₁₂O₆+ 6O₂

Chloroplast

Organelle that preforms photosynthesis

Thylakoid disk

membrane of the chloroplast folded up (inside the chloroplast), contain chlorophyll

Thylakoid membrane

membrane in which pigments are embedded

Granum

a stack of thylakoid disks (grana if plural) the unit that collects light

Light dependent reactions

set of reactions in photosynthesis that use energy from light to produce ATP and NADPH

Photosystems I and II

light-harvesting units of a chloroplast's thylakoid membrane

electron acceptor molecule

A reactant that gains an electron and is reduced in a reduction-oxidation reaction.

Electron transport chains

the series of molecules through which excited electrons are passed along a thylakoid membrane during light dependent reactions

NADP+

carrier molecule that transfers high-energy electrons and other molecules

NADPH

NADP+ carrying electrons and hydrogen (to the stroma for the Calvin Cycle during photosynthesis)

In order o make up for "lost" electrons and hydrogen in LDR

H2O is broken down into hydrogen ions, oxygen, and electrons, which is also how plants produce oxygen

Light Independent Reactions (Calvin Cycle)

use energy from the light dependent reactions to make sugars (happens in the stroma)

Rubisco enzyme

Splits the 6 carbons into 2 groups of 3 carbon molecules (PGA)

PGA

phosphoglycerate; a three-carbon molecule formed in the first step of the Calvin cycle

What is added to the Calvin Cycle that was produced during LDR?

ATP and NADPH, making ADP and NADP+ after their use in the Calvin Cycle

G3P

molecule that is made in the Calvin cycle; glucose is formed when two of these molecules combine

Some G3P are recycled to make

RuBP to start over the Calvin Cycle

RuBP

ribulose biphosphate; a five-carbon carbohydrate that combines with CO2 to form two molecules of PGA in the first step of the Calvin Cycle

During photosynthesis, carbon in CO2 becomes

carbon in C6H12O6

During photosynthesis, oxygen in CO2 becomes

oxygen in C6H12O6

During photosynthesis, hydrogen in H2O becomes

hydrogen in C6H12O6

During photosynthesis, oxygen in H2O becomes

oxygen in O2

Cellular Respiration

Process that produces ATP by breaking down food molecules (specifically glucose)

Formula for cellular respiration

C6H12O6 + O2 -> CO2 + H20

All organisms perform

cellular respiration (or at least some steps)

Heterotrophs

An organism that obtains its food by means of other organisms

Three parts of cellular respiration

glycolysis, citric acid cycle, electron transport chain

Anaerobic process

metabolic process that does not require oxygen

Glycolysis

an anaerobic process, the splitting of sugar that occurs in the cytoplasm (performed by all organisms)

Substrate-level phosphorylation

The formation of ATP by directly transferring a phosphate group to ADP from an intermediate substrate in catabolism.

Product of glycolysis

2 pyruvate

Net gain of ATP in glycolysis

2 ATP

Electron Carriers of Cellular Respiration

NAD+ and FAD

Aerobic process

a metabolic process that requires oxygen

citric acid cycle

an aerobic process, the oxidizing of acetyl Co-A (modified pyruvate) into CO2, occurs in the matrix of the mitochondria

Products of citric acid cycle

2 CO2, 1 ATP, 3 NADH, 1 FADH2

The Citric Acid Cycle takes ___ turns to make one glucose

two

Electron Transport Chain (ETC)

uses the high-energy electrons from the NADH and FADH2 from the Citric Acid Cycle and glycolysis to convert ADP into ATP, occurs in the cristae of the mitochondria

Oxygen is necessary to make

ATP

The oxygen we breathe becomes ___ at the end of the ETC

H2O

The carbon from the food we eat becomes___ at the end of the Citric Acid Cycle

CO2

Fermentation

Returns NADH to NAD+, which is necessary for glycolysis to occur

Anaerobic organisms must

perform glycolysis and fermentation to survive

strict anaerobes

Organisms that can't survive in an atmosphere of oxygen

Facultative anaerobes

Organisms that can survive with or without oxygen

Fermentation begins at the end of

glycolysis

Substrate for fermentation

pyruvate

Fermentation takes place in the

cytoplasm