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Test 2

Catabolic pathways

breaking down complex molecules to simpler compounds "breakdown pathways"

Anabolic pathway

consumes energy to buld complicated molecules from simpler ones "biosynthetic pathways"

Bioenergetics

the study how energy flows through living organisms

Engery

capacity to cause change

Kinetic engery

energy can be associated with the relative motion of objects

Heat/thermal energy

kinetic energy associated with the random movement of atoms or molecules

Potential energy

energy that matter possesses because of its location or structure

Chemical energy

term used by biologists to refer to the potential energy available for release in a chemical reaction

thermodynamics

the study of energy transformation that occur in a collection of matter

first law of thermodynamics

the energy of the universe is constant: energy sn be transferred and transformed, but it cannot be created or destroyed. also known as the principle of conservation of energy

entropy

measure of disorder, or randomness

second law of thermodynamics

every energy transfer or transformation increases the entropy of the universe

spontaneous process

a process that can occur without an input of energy

free energy

the portion of a system's energy that can perform work when temperature and pressure are uniform throughout the system, as in a living cell

exergonic reaction

"energy outward" proceeds with a net release of free energy. energy released, spontaneous

endergonic reaction

"energy inward" one that absorbs free energy from its surroundings.energy required, non spontaneous

chemical work

the pushing of endergonic reaction that would not occur spontaneously, such as the synthesis of polymers from monomers

transport work

the pumping of substances across membranes against the direction of spontaneous movement

mechanical work

such as the beating of cilia, the contraction of muscle cells, and the movement of chromosomes during cellular reproduction

energy coupling

the use of exergonic process to drive an endergonic one

ATP

responsible for mediating most energy coupling in cells, and in most cases it acts as the immediate source of energy that power cellular work

enzyme

macromolecule that acts as a catalyst

catalyst

a chemical agent that speeds up a reaction without being consumed by the reaction

activation energy

the initial investment of energy for starting a reaction

active site

a pocket or groove on the surface of the enzyme where catalysis occurs

induced fit

chemical groups of the active site into positions that enhance their ability to catalyze the chemical reaction

substrate

the reactant an enzyme acts on is referred to as the enzyme's _____

enzyme-substrate complex

the enzyme binds to its substrate

competitive inhibitor

reduce the productivity of enzymes by blocking substrate from entering active sites

noncompetitive inhibitors

do not directly compete with the substrate to bind the enzyme at the active site . Instead they impede enzymatic reactions by binding to another part of the enzyme. this interaction causes the enzyme molecule to change its shape in such a way that the active site becomes less effective at catalyzing the conversion of substrate to product

feedback inhibitor

a metabolic pathway is switched off by the inhibitor binding of its end product to an enzyme that the inhibitory binding of its end product to an enzyme that acts early in the pathway

cell division

unicellular organisms reproduce by this

cell cycle

an order sequence of events in the life of a cell form its origin until it divides into daughter cells

genome

a cell's endowment of DNA, its genetic information

chromosomes

DNA is manageable because the DNA molecules are package into structures called ___

chromatin

the entire complex of DNA and proteins that is the building material of chromosomes

stomatic cell

any body cell except the reproductive cells

gametes

sperm or eggs

sister chromatids

duplicated chromosome, which are joined copies of the original chromosome

centromere

a region containing specific DNA sequences where the chromatid is attached most closely to its sister chromatid

Mitosis

the division of the genetic material in the nucleus

cytokinesis

the division of the cytoplasm

mitotic (M) phase

includes both mitosis and cytokinesis, usually the shortest part of the cell cycle

G1 phase

first gap in cell cycle

S phase

synthese in cell cycle

G2 phase

second gap in cell cycle

cell cycle

In a dividing cell, mitotic (M) phase alternates with interphase, a growth period. the first part of the interphase (G1) is followed by the S phase, when the chromosomes duplicate; G2 is the last part of interphase. In the M phase mitosis distributes the daughter chromosome to daughter nuclei and cytokinesis divides the cytoplasm producing two daughter cells, the relative duration of G1, S, and G2 may vary

Stages in mitosis

prophase, prometaphase, metaphase, anaphase and telophase

mitotic spindle

apparatus of microtubles that controls chromosome movement during mitosis

centrosomes

a subcellular region containing materials that functions throughout the cell cycle to organize the cell's microtubles. spindle microtubules start here

aster

a radial array of short microtubules, extends from each centrosome

kinetochore

a structure of proteins associated with specific sections of chromosomal DNA at each centromere

cleavage

animals carrying out mitosis in cytokinesis

cell plate

plants carrying out mitosis in cytokinesis

binary fission

A form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size

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