Exam 3 OCT 25 Flashcards

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1
Q

Define Metabolic Pathways

A

series of chemical reactions; either build a
molecular complex or break it down

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2
Q

Define Catabolic

A

releases energy by breaking down complex molecules
into simpler ones; “downhill”

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3
Q

Define metabolism

A

totality of an organism’s chemical reactions, management of organism’s energy and resources

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4
Q

Define anabolic

A

consumes energy to build/synthesize a complex
molecule; “uphill”

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5
Q

What are the 4 forms of energy?

A

Kinetic, thermal, potential, chemical

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6
Q

Thermodynamics

A

study of energy transformation that occurs
in a collection of matter

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7
Q

Define system

A

Matter under study

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8
Q

Define surroundings

A

Everything outside the system, not being studied

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9
Q

What is an open system

A

A system where energy and matter can be transferred in/out to surroundings

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10
Q

1st law of thermodynamics

A

Energy can’t be created or destroyed because it is constant

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11
Q

What is the second law of thermodynamics?

A

things in the universe tend to go from
order to disorder; increase Entropy

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12
Q

Entropy

A

Measure of randomness or disorder/chaos in the system

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13
Q

What is a spontaneous Process?

A

process that can happen on its own without requiring energy;
leads to increase in Entropy of universe

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14
Q

What is a nonspontaneous process?

A

process that will only occur if energy is supplied

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15
Q

What is G

A

Free energy

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16
Q

If G is negative, the reaction is what? If G is positive?

A

Negative G= spontaneous
Positive G= non spontaneous

17
Q

What come with having HIGH G?

A

GREATER WORK CAPACITY
MORE FREE ENERGY AVAILABLE LESS
STABLE

18
Q

IN A SPONTANEOUS (HIGH G) REACTION:

A

Free energy of the system decreases
❏ System becomes more stable
❏ The released free energy can be harnessed to do work

Examples of high G reaction: difffuison (high to low), glucose broken down into smaller molecules

19
Q

Define exergonic reaction

A

Net release of free energy; G energy decreases

20
Q

Endergonic reaction

A

Net absorption/storage of free energy; G increases

21
Q

What happens if a living cell reaches equilibrium?

A

It dies

22
Q

What are the three main kinds of work in the cell, and what do they do?

A

Chemical work- endergonic synthesis of monomers to polymers
transport work- pumping substances across membranes
mechanical work- cilia beating, muscle contractions, etc

All of this work is powered by ATP

23
Q

What is energy coupling?

A

the way cells manage their energy resources; use of exergonic process to drive an endergonic one

24
Q

What are the two ways that ATP drives transport and mechanical work?

A
  1. Directly- phosphorylation of membrane proteins carrying out Active Transport of solute against gradient
  2. Indirectly -non-covalent binding of ATP and its hydrolytic products, as in the case for motor proteins
25
Q

If a reaction is spontaneous, what is true about G (free energy)

A

It’s negative

26
Q

Give an example of an exergonic reaction

A

Cellular respiration

27
Q

Use of an exergonic reaction to power a endergonic reaction is called what?

A

Energetic coupling

28
Q

Where is energy in ATP stored?

A

The peptide bonds of phosphates

29
Q

Define enzyme

A

Macromolecules that act as catalysts

30
Q

Define catalyst

A

chemical agent that speeds up reaction without
being consumed by reaction

31
Q

What is activation energy

A

the energy required to contort
the reactant molecules so the bonds can break (initial energy investment for starting reaction); determines the rate of reaction; acts as a barrier to rate; often supplied by thermal energy

32
Q

Define transition state

A

when reactants are in unstable condition due
to molecules absorbing enough energy to break bonds

33
Q

Define catalysis

A

process by which an enzyme (catalyst) selectively speeds up reaction without being consumed; can only speed up spontaneous (exergonic) reactions; ends in -ase*

34
Q

What is a cofactor? Give an example of a molecule that acts as a cofactor.

A

Non-protein (inorganic) enzyme helper
​Ex: iron, zinc

35
Q

Define Allosteric Regulation. How do these affect a cell? Give an example of a pathway that uses Allosteric Regulation

A

Allosteric Regulation- protein’s function at one site is affected by the binding of a regulatory molecule at another site. It can either inhibit or activate pathways. Used for hormones and gene regulation.
Ex: Acetyl-CoA Carboxylase–regulated by negative feedback (product) and hormones, like glucose and epinephrine; used for lipogenesis