Shared Flashcard Set

Details

Prelim 2
ahhh!
98
Biology
Undergraduate 1
10/30/2008

Additional Biology Flashcards

 


 

Cards

Term
metabolism 
Definition
all the chemical reactions of an organism
Term
catabolic vs. anabolic pathways 
Definition

catabolic- degradative, spend energy

anabolic-  consume energy

Term

heat/thermal energy

 

Definition
kinetic energy associated with random movement of atoms
Term
chemical energy
Definition
potential energy available for a reaction
Term
first law of thermodynamics
Definition
energy cannot be destroyed
Term
second law of thermodynamics
Definition
entropy (disorder) is always increasing
Term
spontaneous
Definition
can occur without an input of energy
Term
free energy
Definition

=G (Gibbs free energy)

a system's energy that can perform work

G=H-TS

 

-G =spontaneous 

Term
exergonic reaction
Definition

reaction that occurs with net release of free energy

 

spontaneous reaction

 

 

Term
endergonic reaction
Definition

reaction that occurs with a net absorbtion of energy

 

nonspontaneous 

Term
energy coupling
Definition
using a exergonic reaction to drive an endergoinc reaction
Term

energy change

ATP to ADP 

Definition

exergonic reaction

realeses 7.3 kcal of energy under standard conditions and about 13 kcal in cellular condition

 

negatively charged phosphate groups contribute to instability of ATP

 

Term
regeneration of ATP
Definition

energy comes from exergonic reactions in cell

 

ex. light energy and cellular respiration 

 

 

Term
catalysts and activation energy
Definition

speeds up a reaction without being consumed

 ex. enzymes 

 

activation energy is the energy needed to start the "downhill" part of the reaction

present in all exergoinc reactions and determines the rate of the reaction 

Term
enzymes
Definition

lower activation energy barrier

binds to substrate with H or ionic bonds

converts the substrate to the product 

Term
4 ways enzymes reduce energy barrier
Definition

provide template

 

stressing the substrate and stablizing the transition

 

provide a ideal microenvironment

 

participating directly in reaction 

 

 

Term
cofactors
Definition

helpers for catalysts

 

can be permanent or bind loosely 

Term
enzyme inhibitors
Definition

competitive- block substrates from active site

 

noncompetitive- bind to another part of the enzyme 

Term
allosteric regulation
Definition

protein's function at one site is affected by the binding of a regulatory molecule at another site

 

(ATP is an inhibitor and ADP is a promoter regulatory molecule) 

Term
cooperativity
Definition
when one substrate molecule binds and increases the affinity for more substrate molecules
Term
aerobic respiration
Definition
oxygen is consumed as a reactan along with organic material
Term
cellular respiration
Definition

technically means both anaerobic and aerobic respiration

(usually means aerobic)

 

helpful to learn steps using glucose breakdown into CO2 H2O and energy 

 

3 steps- glycolysis, the citric acid cycle and oxidative phosphorylation 

Term
redox reaction of cellular respiration
Definition

glucose becomes oxidized into carbon dioxide

 

oxygen becomes reduced into water 

Term
NAD+
Definition

hydrogen atoms are not directly transferred to oxygen but to elctron carrier NAD+

 

oxidizing agent

 

coenzyme 

Term
dehydrogenase
Definition
takes 2 hydrogens from glucose and adds 2 electons and one proton to NAD+ and leaves one electon as H+
Term
electron transport chain
Definition

breaks the fall of electrons to oxygen into several energy releasing steps

 

each downhill step is more electronegative than and capable of oxidizing the previous step 

 

collection of molecules embedded in inner membrane of mitochondrion 

 

doesn't form ATP! 

Term
glycolysis
Definition

1st step of cellular respiration

occurs in the cytosol

breaks down glucose into 2 3-carbon sugars which are oxidized and rearranged into 2 pyruvates 

 

produces 2 ATP and 2 NADH

 

occurs whether or not oxygen is present

 

2 phases- energy investment and energy payoff 

Term
citric acid cycle
Definition

takes place in the mitochondrial matrix of eukaryotes or in the cytosol of prokaryotes

 

oxidizes a derivative of pyruvate to carbon dioxide 

 

first converted to acetyl CoA before it happens

 

forms 1 ATP/GTP, 3 CO2, 3 NADH and FADH2 

 

 

Term
oxidative phosphorylation
Definition

3rd step of cellular respiration

 

electron transport chain accepts electrons and passes them to H+ forming water

 

energy released is stored so it can make ATP 

Term
substrate level phosphorylation
Definition

how ATP is formed during glycolysis and the citric acid cycle

 

adding a phosphate group from the substrate molecule instead of an inorganic phosphate as in oxidative phosphorylation 

Term
energy investment phase of glycolysis
Definition

2 ATP used

 

glucose is phophorylated by hexokinase- makes it stay in cell and makes it more reactive

 

glucose-6-phosphate is converted to fructose-6-phosphate

 

another phosphate group is added

 

aldolase cleaves the sugar into 2 different 3 carbon sugars (isomers)

 

isomerase converts one isomer to the other- only glyceraldehyde-3-phosphate is used next 

Term
payoff phase of glycolysis
Definition

produces 4 ATP and 2 NADH

 

enzyme catalyses 2 reaction- sugar is oxidized forming NADH and energy from this is used to attach phosphate group (high potential energy)

 

phosphate group is used to make ATP, no longer a sugar

 

phosphate group is relocated

 

enzyme causes double bond and extracts water, high potential energy

 

pyruvate is formed by the release of phosphate group to ATP  

Term

anaerobic respiration

 

Definition
no oxygen present- uses electron transport chain but something else as the electron acceptor
Term
fermentation
Definition

no transport chain and no oxygen

 

expansion of glycolysis that provides more ATP by substrate-level phosphorylation

 

needs to be a sufficient supply of NAD+  

Term
alcohol fermentation
Definition

pyruvate is converted to ethanol

 

1st step releases CO2

2nd step it is reduced by NADH to ethanol (regenerates NAD+)

Term
lactic acid fermentation
Definition
pyruvate is directly reduced by NADH
Term
formation of acetyl CoA
Definition

pyruvate's carboxyl group is removed as CO2

 

carbon fragment is oxidized- forming NADH

 

coenzyme A is attached by unstable bond  

Term
8 steps of citric cycle
Definition

1. acetyl CoA adds its acetyl to oxaloacetate to produce citrate

2. citrate is converted to its isomer by removal and addition of H2O

3. isocitrate is oxidized, forming NADH, CO2 is lost

4. another CO2 is lost and compound is oxidized, forming NADH, then attached to coenzyme A 

5. coA is displaced by phosphate group which is then added to GTP

6. 2 hydrogens are transferred to FAD

 7. addition of water molecule

8. substrate is oxidized, forming NADH, regenerate oxaloacetate 

Term
cytochromes
Definition
has a heme group that readily accepts and donates electrons, in transport chain
Term
chemiosmosis and ATP synthase
Definition

energy stored in the form of hydrogen ion gradient across a membrane used to drive cellular work

 

atp synthase- rotary motor

[image]

Term
reasons that ATP numbers are not exact
Definition

phosphorylation and redox are not directly coupled

 

depends on the type of shuttle used to transfer electons from cytosol to mitochondria

 

proton motive force drives other processes 

Term
phosphofructokinase
Definition

pacemaker of cellular respiration

 

catalyzes step three of glycolysis- first step that commits the sustrate irreversibly

 

allosteric enzyme- inhibited by ATP and stimulated by AMP

 

sensitive to citrate- inhibits 

 

Term
mesophyll
Definition

interior tissue of leaf

 

each cell typically holds 30-40 choloplasts  

 

2 membranes- holds stroma and thylakoids 

Term
thylakoids
Definition

interconnected membranous sacs that segregate stroma from the thylakoid space

 

chlorophyll resides inthe thylakoid membrane  

Term
splitting of water in photosynthesis
Definition

oxygen given off by plants comes from water not from CO2

 

different organisms uses different sources for thier H 

Term
2 stages of photosynthesis
Definition

light reactions(thylakoids) and Calvin cycle(stroma)

 

light reactions- water is split and hydrogens are transferred to NADP+, generates ATP using chemiosmosis (Photophosphorylation)

 

Calvin Cycle- carbon fixation, reduces fixed carbon with NADPH and ATP

 

Term
carbon fixation
Definition
incorporating carbon dioxide from the atmosphere into organic compunds that are already present
Term
cartenoids
Definition

accessory pigments

 

hydrocarbos that are yellow and orange

 

may broaden teh spectrum that can drive photosynthesis but they more importantly protect against excessive light energy 

Term
photosystem
Definition

composed of a reaction-center complex surrounded by several light harvesting complexes

 

converts light energy to chemical energy 

 

pigments in LHC absorb energy and pass electron from pigment to pigment until it reaches RCC and two special chylorophyll a pass electron on to primary electron acceptor

 

two types- I and II

 

[image]

Term
excitation of chlorophyll
Definition
molecule absorbs photon and an electon is excited toa higher orbital
Term
linear electron flow
Definition

flow of electrons through the photosystems and other components of the thylakoid membrane

 

1. photon absorbed and transferred from the excited P680 to primary electron acceptor  

2. water is split, electrons are suplied to P680+ and O2 forms

3. photoexcited electron moves to electon acceptor in PSI (P700+ forms) with electron transport chain

4. proton gradient is created and available for ATP synthesis 

5. electrons are passed from electron acceptor in PSI to ferredoxin

6. electron transfer from Fd to NADPH (2 e- required)  

Term
cyclic electron flow
Definition

uses photosystem I but not II

 

generates ATP but not NADPH

 

evolutionary leftover

Term
Calvin cycle
Definition

uses ATP and NADPH to convert CO2 to sugar (glyceraldehyde-3-phosphate)- takes three cycles to make one

(for on G#P- 9 ATP, six NADPH) 

 

1. carbon fixation- rubisco helps attach CO2 to 5 carbon sugar- so unstable it splits into 2

 

2. reduction- recieves phosphate group and NADPH reduces and phoshate is removed, 6 G3P formed from 3 CO2 but only one exits cycle,other are used to regenerate RuBP 

 

3. regeneration- spends three more ATP  

 

 

Term
photorespiration
Definition

when CO2 is lacking

rubisco in C3 plants binds oxygen instead of carbon dioxide

produces no sugar and no ATP 

 

drains away fixed carbon- seems counterproductive 

Term
C4 plants (STUDY!!!)
Definition

form a four carbon sugar as first product

 

leaf anatomy- 2 types of photosynthetic cells- bundle sheath (calvin cycle) and mesophyll (fixation)

 

1.  PEP carboxylase adds CO2 to PEP forming the 4 carbon product

2. mesophyll cells export thier 4-carbon product to bundle sheath cells through plasmodesmata

3. coupounds release CO2 whihc is made back into organic material 

Term
CAM
Definition

used in arid climates

stomata open during the night and close during the day 

Term
origin of multicellularity
Definition

common ancestor lived 1.5 billion years ago

 

relatively small algae 

Term
signal transduction pathway
Definition
process by which a signal on a cell's surface is converted to a cellular response
Term
hormone
Definition
used fro long distance cell signaling
Term
ligand
Definition

molecule that specifically bind to another

 

 generally causes receptor to change shape

Term
G protein receptor
Definition

seven alpha helices that span the membrane

 

signaling molecule binds and attracts G protein with GDP and activates the protein

 

the activated G protein bind to an enzyme and it triggers the next response

 

becomes inactivated 

Term
receptor tyrosine kinases
Definition

have enzymatic activity

 

2 signaling molecules bind and the 2 proteins combine 

 

phosphorylation of each tyrosine

 

relay proteins bind to tyrosine and celllar response ensues 

Term
protein kinase
Definition
enzyme that transfers phosphate group from ATP to protein
Term
protein phosphatases
Definition
enzymes that can rapidly move phosphate groupsfrom proteins
Term
second messengers
Definition

water soluble molecules or ions

 

ex. cyclic AMP and Ca2+  

Term
cyclic AMP
Definition

adenylyl cyclase converst ATP to cAMP

 

immediate effect of cAMP is hte activation of kinase A which then phophorylates other proteins 

Term
IP3 and DAG
Definition

second messengers that help in release of CA2+ messenger

 

Term
innate immunity
Definition

found in all animals

active immediately upon infection 

Term
acquired immunity
Definition

only found in vertebrates

activated after innate immune defenses take effect

develop more solwly 

Term
innate immunity of invertebrates
Definition

exoskeleton

 

lysozyme- digest microbial walls

 

hemocytes- phagocytosis, trigger production of chemicals and antimicrobial peptides

Term
innate immunity of vertebrates
Definition
barrier defenses, phagocytosis, antimicrobial peptides,  inflammatory response and natural killer cells
Term
leukocytes
Definition

toll-like receptors on the surface  trigger phagocytosis and then fuse with lysosome and gases and enyzmes destroy microbial components

Term
types of phagocytes
Definition

neutrophils

macrophages

eosinophils

dendritic cells 

Term
interferons
Definition
proteins that provide innate defenses against viral infections
Term
developmental plasticity
Definition
ability to alter form in response to environment
Term
morphology
Definition
external form
Term
taproot system
Definition

one main vertical root that develops from an embryonic root with lateral roots branching from it

 

stores sugars and starches 

Term
fibrous root system
Definition
when the embryonic root dies and many small roots grow from the stem
Term

nodes

 

internodes

Definition

points at which leaves are attached

 

stem segments between nodes 

Term
axillary bud
Definition
can form a lateral shoot
Term
petiole
Definition
stalk of a leaf, joins the leaf to node
Term
arrangement of veins
Definition

monocots - parallel major veins

 

eudicots - branched network of major veins 

Term
trichomes
Definition
hairlike extensions of the shoot system epidermis
Term
stele
Definition

the vascular tissue of root or stem

 

vascular cylinder in root

vascular bundles in stems and leaves 

Term
pith
Definition
ground tissue internal to the vascular tissue
Term
cortex
Definition
ground tissue external to vascular tissue
Term
parenchyma cells
Definition

have large central vacuole

 

perform metabolic functions (eg. photosynthesis)

 

can divide and differentiate

 

thin and flexible primary walls 

Term
collenchyma cells
Definition

grouped in strands or cylinders

 

flexible support

 

thick primary walls 

Term
sclerenchyma cells
Definition

have secondary walls with lignin

 

less flexible support

 

many are dead at maturity 

Term
water conducting cells of the xylem
Definition

tubular elongated cells, dead at maturity 

 

tracheids- long, thin, tapered 

 

vessel elements- wider, shorter, thinner and less tapered 

Term
sugar conducting cells of the phloem
Definition

alive at functional maturity

 

sieve cells- lack nucleus, ribosomes, a vacuole and cytoskeleton

 

have companion cells 

Term
meristems
Definition

perpetually embroynic tissues- allows for indeterminate growth 

 

apical (primary growth) or lateral (secondary growth)

Term
vascular cambium
Definition
adds layers of secondary xylem and phloem
Term
cork cambium
Definition
replaces epidermis with periderm
Term
three zones of primary growth
Definition

cell division

elongation

differentiation 

Term
endodermis
Definition
innermost layer of cortex
Term
pericycle
Definition

outermost cell layer in the vascular cylinder

from where the lateral roots arise 

Term
leaf primordia
Definition

projections along the sides of the apical meristem

 

leaves develop from them 

Supporting users have an ad free experience!