Bio exam 6-9

If monomers are joined in a reaction it is called:

anabolic

Free energy is released in:

catabolic reactions

Activation energy is NOT required for catabolic reactions.

false

Entropy or conversion of energy to an unstable state, is part of the:

2nd law of thermodynamic

Enzyme action may be inhibited by all of the following EXCEPT:

presence of cofactors

All energy enters the earth's biosphere from the:

sun

Metabolism refers to only catabolic reactions of a cell or organism.

false

endergonic

exergonic

Breaking bonds in which part of the ATP molecule provide energy for reactions in the cell?

phosphate group

An allosteric INHIBITOR does which of the following?

Binds to the active site and blocks it from binding substrate

Most enzymes are proteins.

true

Plants store energy via photosynthesis in the bonds of:

glucose

Which of the following statements about endergonic and exergonic reactions is false?

Endergonic reactions take place slowly and exergonic reactions take place quickly

Photosynthesis is a catabolic pathway.

false

In cellular respiration the energy in the bonds of glucose is transferred to:

bonds of phosphates in ATP

When a molecule is oxidized it

lose electrons

The majority of ATP is produced by which set of reactions?

oxidative phosphorylation

All of the following occurs in mitochondria EXCEPT:

glycolysis

Glycolysis can occur in anaerobic conditions as long as _________ is regenerated using fermentation.

NAD+

Which wavelength of light is best for photosynthesis?

blue

All of the following are photosynthetic pigments EXCEPT:

melanin

Which of the following occurs in membranes of the thylakoids?

light dependant reactions

Which component uses ATP, NADPH & CO2 to build glucose?

Calvin Cycle, Light Independent Reactions or Dark Reactions

In which of the following is H2O split to generate H+ and oxygen?

Photosystem II

Chemiosmosis involves

movement of hydrogen ions across a mitochondrial membrane

The energy currency used by cells is

ATP

A reducing chemical reaction

adds an electron to the substrate in the form of a H atom

Which pathway receives electrons from NADH?

ETC

At the end of glycolysis, a small amount of ATP is made.

true

What is the source of electrons for the chloroplast electron transport chain?

water

What two main products result from photosynthesis?

sugars/carbohydrates and oxygen

Which statement about thylakoids in eukaryotes is NOT correct?

Thylakoids exist as a maze of folded membranes

Which molecule must enter the Calvin cycle continually for the light-independent reactions to take place?

CO2

The photosynthesis equation is the reverse of cellular respiration.

true

Cells that produce signals that act on neighboring cells are called:

paracrine

Signal molecules that can go directly through the cell membrane to find their receptors inside are called:

hydrophobic

The passing of a signal from the outside to the inside of the cell across the cell membrane is called:

signal transduction

All of the following are cell surface receptors EXCEPT:

steroid intracellular

Another name for Apoptosis

programmed cell death

Neurotransmitter released and binding on adjacent neurons.

paracrine signaling

The secretion of hormones by the pituitary gland into the bloodstream.

endocrine signaling

The release and binding of IL-1 ligand on the same monocyte

autocrine signaling

Coordination of contraction in connected cardiac muscle cells.

direct signaling across gap junctions

Which type of molecule acts as a signaling molecule in yeasts?

mating factor

All of the following are considered second messengers except:

tyrosine kinase

Why are ion channels necessary to transport ions into or out of a cell?

Ions are charged particles and cannot diffuse through the hydrophobic interior of the membrane

Apoptosis can occur in a cell when the cell is:

damaged, no longer needed, infected by a virus

Endocrine signals are transmitted more slowly than paracrine signals.

true

Cell signaling can result in:

increased cell metabolism, cell growth, cell death

metabolic pathway

series of biochemical reactions that converts one or more substrates into a final product

Gibb’s free energy

amount of energy available to do work

Activation energy

energy required for reaction to happen

1st law of thermodynamics

all energy in universe is constant, energy cannot be created or destroyed

2nd law of thermodynamics

the transfer of energy is not completely efficient

• with each reaction some energy is lost

ATP composition

adenosine backbone and 3 phosphate groups

sodium-potassium pump

energy from ATP hydrolysis used to move 3 sodium ions out and 2 potassium ions in

enzymes

protein catalysts that speed up reactions

enzyme regulation

helps control cell environment to meet specific needs

• temp or pH

competitive enzyme inhibition

inhibitor has similar shape to substrate and competes for active site

noncompetitive enzyme inhibition

bind to enzyme at different location slowing down reaction rate

allosteric inhibitors

modify active site of enzyme so that substrate binding is reduced or prevented

allosteric activators

modify active site of enzyme that substrate binding is increased

enzyme cofactors

one or more required for enzyme function

feedback inhibition

end product of pathway inhibits upstream step

redox reaction

electrons transferred from one molecule to another

reducing agent

donate electron in redox reaction

oxidizing agent

accept electron in redox reaction

phosphorylation

adding a phosphate group to a molecule

hydrolysis of ATP

ADP+Pi

90% of ATP is produced by

chemiosmosis

cellular respiration reaction

C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + ~36 ATP

Metabolic pathways involved with cellular respiration

glycolysis, oxidative phosphorylation, citric acid cycle, oxidation of pyruvate

glycolysis(in)

1 glucose, 2 NAD+, 2 ATP, 4 ADP

glycolysis(out)

2 pyruvate, 2 NADH, 4 ATP, 2 ADP

glycolysis

• occurs in cytoplasm

• 10 enzymatic reactions

• anaerobic

oxidation of pyruvate

if oxygen is present —> 2 pyruvate enter mitochondria —> converted to Acetyl CoA

• beginning of citric acid cycle

citric acid cycle

occurs in mitochondrial matrix

citrate oxidized —> 3 NADH + 1 FADH2 made and CO2 released —> 1 GTP/ATP produced

—> oxaloacetate

citric acid cycle (out per glucose)

4 ATP, 6 CO2, 10 NADH, 2 FADH2

oxidative phosphorylation(structure)

ETC and chemiosmosis

oxidative phosphorylation(ETC)

electrons from NADH and FADH2 moved to O2 —> redox reactions+energy released —> proton gradient

oxidative phosphorylation(chemiosmosis)

uses kinetic energy from protons in gradient to create ATP(~36)

which process creates the most ATP

oxidative phosphorylation

lactic acid fermentation

occurs in muscle cells when O2 is limited

pyruvate + NADH ←→ lactate + NAD+

metabolism without O2

fermentation regenerates NAD+ so glycolysis can continue

alcohol fermentation

anaerobic yeast species

• catalyzed by pyruvate decarboxylase —> alcohol dehydrogenase

autotrophs

self-feeding organisms

photoautotrophs

use sunlight to make food

• plants, algae, cyanobacteria

chemoautotrophs

capture energy from inorganic chemicals

• thermophilic bacteria

heterotrophs

rely on autotrophs for energy, heterotrophs eat other heterotrophs for energy

photosynthesis equation

6 CO2 + 6 H2O —> C6H12O6 + 6 O2

metabolic pathways of photosynthesis

light dependent reaction

calvin cycle

light reaction

converts light energy to chemical energy

• occurs in thylakoid membrane of chloroplasts

calvin cycle

uses ATP and NADPH to make sugar

• occurs in stroma of chloroplasts

chloroplast structure

double membrane, stroma, grana(stacks of thylakoids), lumen(inside thylakoid)

main pigments of thylakoid membrane

chlorophyll a, chlorophyll b, B-carotene

thylakoid membrane components

Photosystem I and II, ETC molecules, NADP reductase, ATP synthase

Photosystem II

1st system

absorbs light energy and uses it to transport electrons from H2O to the ETC, producing O2 as a byproduct

Photosystem I

2nd system

uses light energy to transport electrons to NADP+, forming NADPH

stages of calvin cycle

fixation, reduction, regeneration