AP bio unit 3

Enzymes

Proteins that speed up chemical reactions

What structure must enzymes maintain?

Tertiary

Active site

Region of an enzyme that interacts with the substrate

Substrate

Any molecule that can interact with an enzyme

Are enzymes changed by the reaction?

No, they are not changed and are reusable

Activation energy

The initial starting energy required by a biochemical reaction.

What do enzymes do to activation energy

They lower it

Negative control

The subjects are not exposed to any treatment, experimental or not. They are unchanging.

Positive control

The subjects are exposed to a treatment with a known effect.

Denaturation

Hanged in the conformational shape (tertiary structure) of an enzyme

What affects denaturation

Changes in temperature and PH

How does denaturation impact an enzyme?

Typically irreversible. Either destroys or decreases the enzymes catalytic ability.

Environmental increase in temperature

Initially increases reaction rate

• increased speed of molecular movement increased the frequency of enzyme-substrate collisions

Once temperature increases outside of optimal range, the enzyme denatures

Environmental decrease in temperature

Slows down reaction rate

• molecules slow and enzyme-substrate collisions decrease

Doesn’t disrupt enzyme function

What is the most neutral on the PH scale?

7

Acidic vs alkaline numbers

• less than 7 are acidic

• More than 7 are alkaline

Increase in substrate concentration

Initially increases reaction rate

• more substrates allows more opportunity for collision with enzymes

Substrate saturation occurs

• no further increase in the rate of

• Reaction rate will remain constant if saturation levels are maintained

Increase of product

Decreases the opportunity for the addition of substrate

• matter takes up soace

• More product lowers the chance of enzyme-substrate collisions

• Slows reaction rate

Competitive inhibitor

Molecules that bind irreversibly or reversibly to the active site of an enzyme (not the substrate)

• if their concentration exceeds the substrate then the reaction is slowed

Noncompetitive inhibitor

Binds to a region of an enzyme called the allosteric site

• does not bind to the active site

• Causes a conformational shape change

• Prevents enzyme function because the active site is no longer available

• Slows reaction rate Once temperature

• Increasing substrate levels does not affect the inhibitor

Autotrophs

Capture energy from physical sources (sunlight) or chemical sources and transform into usable energy for their cells.

What happens to some energy during every energy transformation

It is unusable and lost as heat

Second law of thermodynamics

Every energy transfer increases the disorder of the universe

Energy coupling

Energy releasing processes drive energy storing processes

Photosynthesis

The biological process that converts energy from the Sun into sugars.

Where do the light dependent reactions take place

In the thylakoid membranes

How do the Light dependent reactions use the sun

Use light absorbing molecules called pigments

• the pigments help transform the light energy into chemical energy

Thylakoids

Disc-like structures in a chloroplast that help absorb light

Grabs

Stacks of thylakoids

Chlorophyll

Pigments found in the thylakoids that absorbs light energy to produce carbs

Stroma

Fluid filled space surrounding the grana

what molecules are made in thee light dependent reactions

NADPH, ATP, and O

What is chlorophylls role in boosting electron energy levels

It captures the energy from sunlight and converts it to high energy electrons

What happens to chlorophyll electrons when light absorption occurs?

They’re energized.

• the energy will be used to established a proton gradient and reduce NADP+ to NADPH

Where are the photo systems

Embedded in the internal membranes of chloroplasts

Why is the hydrolysis of water necessary?

The hydrogen molecules are released into the thylakoid spaced and used to create an electrochemical/proton gradient.

How are the photosystems functionally related to the ETC

They pass high energy electrons the ETC

Photo system

A light capturing unit in a chloroplasts thylakoid membrane

Electrochemical/proton gradient

Difference in the concentration of protons (hydrogen ions) across a membrane

How does photosynthesis generate ATP

It uses a form of passive transport to generate ATP from ADP

What is ATP synthase

The enzyme that creates ATP when protons pass through the enzyme

What does the Calvin cycle use and produce

• Uses: ATP, NADPH, and CO2

• Produces: Carbohydrates

What is the ultimate goal of the Calvin cycle

Make organic products that plants need using the products of the previous reactions

Fermentation and cellular respiration

Processes that allow organism to use stored energy

Difference between fermentation and cellular respiration

Fermentation does not use oxygen. Cellular respiration does use oxygen.

Cellular respiration

Glucose is broken down and ATP is created

Glycolysis

Occurs in the cytoplasm

Pyruvate oxidation

Occurs in the mitochondria

Krebs/citric acid cycle

Occurs in mitochondria

ETC

Occurs in mitochondria

• facilitates a series of coupled reactions to transfer energy from electrons

What electron carriers deliver electrons to the ETC in cellular respiration

NADH and FADH2

What makes up the ETC

Membrane proteins

Relationship between the ETC and protons

The ETC uses protons to create a proton gradient

How are proton gradients maintained?

The membrane is impermeable to ions.

Chemiosmosis

The movement of hydrogen ions down their gradient via ATP synthase.

Oxidative phosphorylation

The process of making ATP using the stored energy of a protons to create gradient

Decoupling oxidative phosphorylation

Proton gradient NOT being used by ATP synthase to make ATP

• energy stored in the gradient is released as heat

• Heat can be used by endothermic organisms to regulate body temperature

What does glycolysis produce

Pyruvate, NADH, and ATP

Where is Pyruvate transported

From the cytosol to the mitochondrion

Then actively transported from the mitochondrial membranes to the matrix

Hat happens to Pyruvate in the mitochondria

It’s oxidized and the product enters the Krebs cycle

What happens in the Krebs cycle

• carbon dioxide is released

• High energy electrons are transferred to NADH and FADH2

• ATP is synthesized from ADP

What are the electron donators in cellular respiration

NADH and FADH2

What are byproducts of fermentation

Ethanol and lactic acid

Individual fitness

An individual organisms ability to survive and reproduce

How does the variation in chlorophyll help plants

It allows different plants to absorb different light, meaning they can survive at different times of the year and in changing environments

How does cholesterol in animal membranes help an organism

Stabilizes the membrane at high temperatures and allows fluidity at lower temperatures.

• structured membranes are critical for homeostasis

Can decrease water penetration

• animal cells don’t have cell walls to counter lysis

• Cholesterol helps restrict the diffusion of water