Chapter 6 Lecture Flashcards

Cells require:

•a membrane separating the inside of the cell from the outside

•a way to encode/transmit information

•energy to do the work of the cell: move, grow, pump ions, and perform reactions necessary for cellular function, among other things

Cells require a _________ separating the inside of the cell from the outside

membrane

Cells require a way to ______________ information

encode/transmit

Cells require ______ to do the work of the cell: move, grow, pump ions, and perform reactions necessary for _____ ______, among other things

energy, cellular function

______ is the capacity to cause change

Energy

Energy exists in various ______, some of which can perform work

forms

___ is the movement of matter against opposing forces, such as gravity and friction

Work

_____ ______ is energy associated with motion

Kinetic energy

_________ _______ is kinetic energy associated with random movement of atoms or molecules

Thermal energy

___ is thermal energy in transfer from one object to another

Heat

_____ is another type of energy that can be harnessed to perform work

Light

________ _______ is energy that matter possesses because of its location or structure

Potential energy

______ ______ is potential energy available for release in a chemical reaction

Chemical energy

Energy can be __________ from one form to another

converted

What is an example of potential energy?

Energy within chemical bonds of a molecule

Catabolism

breakdown of molecules into smaller units, producing ATP

Anabolism

building of molecules from smaller units, requiring an input of energy, ATP

Gibbs Free Energy

ΔG = ENERGY IN PRODUCT – ENERGY IN REACTANTS (ΔG = G_products – G_reactants)

Endergonic Reaction have a

positive ΔG

Exergonic reactions have a

negative -ΔG

ΔG = ΔH - TΔS

S = entropy

H = enthalpy

T = temperature (Kelvin)

G = Gibbs free energy

Δ = “change in”

___ – the energy currency of the cell

ATP

Enzymes work by __________ the energy required to have a reaction

lowering

A reaction with a positive ΔG value is ______

Endergonic

_______ ___ _______ depends on energy needed to activate reaction

Rate of a Reaction

_______ are substances that increase the rate of a chemical reaction without themselves being consumed.

Catalysts

Catalysts are usually proteins called ______

ENZYMES

Enzymes are _______ ________, therefore they play a crucial role in determining which chemical reactions take place.

HIGHLY SPECIFIC

Hydrolysis of sucrose by the enzyme sucrase is an example of an ________ ______ reaction.

enzyme-catalyzed

What is the specific region on the enzyme where the substrate binds?

The active site

In this specific example, identify the enzyme and its target substrate.

The enzyme is lactase and the substrate is lactose.

What are the four main steps of the enzyme cycle shown in the diagram?

1. Ready for substrate 2. Substrate binding 3. Catalysis 4. Product release

What molecule is introduced during the catalysis step to help break down the substrate?

Water (H₂O). Note: This indicates it's a hydrolysis reaction.

What are the specific products released after lactase breaks down lactose?

Glucose and galactose.

Is the process shown in the slide an example of anabolism or catabolism?

Catabolism. (The enzyme is breaking down a larger molecule into smaller, simpler ones).

Is the reaction shown in the slide exergonic or endergonic?

Exergonic. (Catabolic reactions that break chemical bonds typically release energy).

What can affect enzyme activity?

Environmental/local factors like Temperature and pH

Regulation of reaction components

–Switching on or off the genes that encode specific enzymes

–Changing enzyme or substrate concentrations

–Regulating the activity of enzymes

Each enzyme functions best at an optimal:

–Temperature

–pH

Enzymes can be _________ outside of these optimal conditions

denatured

Denatured means:

Unfolded

Regulation of enzyme activity within the cell:

enzyme concentration

What can affect enzyme activity?

■Regulation of reaction components

–Switching on or off the genes that encode specific enzymes

–Changing enzyme or substrate concentrations

–Regulating the activity of enzymes

Inhibitors

decrease the activity of enzymes.

a.Competitive

b.Noncompetitive

c.Negative feed-back

Activators

increase the activity of enzymes.