AP BIO - CH. 6-10 VOCAB

Cell fractionation

takes cells apart and separates the major organelles from one another

cytosol

semifluid, jellylike substance inside all cells which sub cellular components are suspended

Basic features of all cells

plasma membrane, semifluid substance called cytosol, chromosomes (carry genes), ribosomes (make proteins)

Eukaryotes are characterized by having

DNA in a nucleus that is bounded by a membraneous nuclear envelope, membrane-bound organelles, cytoplasm in the region between plasma membrane and nucleus

humans and plants are eukaryotes

nucleus

contains most of the cell’s genes and is usually the most conspicuous organelle

nuclear envelope

encloses the nucleus, separating it from the cytoplasm, consist of a double membrane with each membrane having a lipid bilayer

chromatin

DNA and proteins of chromosomes together

condenses to form discrete chromosomes as cell prepares to divide

ribosomes

complexes made of ribosomal RNA and Protein

protein synthesis is carried out in 2 locations; cytosol (free ribosomes) and outside of the ER of the Nuclear envelope (bound ribosomes)

The endomembrane system consists of

nuclear envelope, ER, Golgi apparatus, lysosomes, vacuoles, plasma membrane

components are either continuous or connected by vesicles

Endoplasmic reticulum (ER)

accounts for more than half of the total membrane in many eukaryotic cells

continuous with the nuclear envelope

smooth ER

no ribosomes

rough ER

studded with, or has, ribosomes

functions of smooth ER

synthesizes lipids, metabolizes carbohydrates, detoxifies drugs and poisons, stores. calcium ions

functions of rough ER

has bound ribosomes which secrete glycoproteins, distributes transport vesicles (secretory proteins surrounded by membranes), is a membrane factory for the cell

lysosome

membraneous sac of hydrolytic enzymes that can digest macromolecules

fluid mosaic model states

a membrane is a fluid structure with a “mosaic” of various proteins embedded in it

proteins aren’t randomly distributed

peripheral proteins

bound to the surface of the membrane

intergal proteins

penetrate the membranes hydrophobic core

intergral proteins that span the membrane are called transmembrane proteins

6 major functions of membrane proteins

transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining, attachment to the cytoskeleton and extracellular matrix (ECM)

glycolipids

membrane carbohydrates covanletly bonded to lipids

glycoproteins

membrane carbohydrates covalently bonded to proteins

transport proteins

allow passage of hydrophilic substances across a membrane

aquaporins

channel proteins that facilitate the passage of water

tonicity

the ability of a surrounding solution to cause a cell to gain or lose water

isotonic solution

solute concentration is the same as that inside the cell; no net water movement

hypertonic solution

solute concentration is grater than that inside the cell; cell loses water

hypotonic solution

solute concetration is less than inside the cell; cell gains water

tonicties in animal and plant cells

osmoregulation

control of solute concentrations and water balance

passive transport vs. active transport

membrane potential

voltage difference across a membrane

electrochemical gradient

two combined forces driving the diffusion of ions across a membrane

a chemical force (ions concentration gradient)

a electrical force (the effect of the membrane potential on the ions movement)

electrogenic pump

a transport protein that generates voltage across a membrane

major electrogenic pump of animal cells

sodium-potassium pump

main electrogenic pump of plants, fungi, and bacteria

proton pump

cotransport

occurs when active transport of a solute indirectly drives transport of other substances

endocytosis

cell takes in macromolecules by forming vesicles from plasma membrane

metabolism

totality of an organisms chemical reactions

metabolic pathway

begins with a specific molecule and ends with a product

catabolic pathways

release energy by breaking down complex molecules In to simpler compounds

EX: cellular respiration

anabolic pathways

consume energy to build complex molecules from simpler ones

EX: synthesis of protein from amino acids

energy

capacity to cause change

kinetic energy

associated with motion

heat/thermal energy

kinetic energy associated with random movement of atoms or molecules

potential energy

energy that matter possesses because of its location or structure

chemical energy

potential energy available for release in a chemical reaction

first law of thermodynamics

energy can be transferred and transformed, but it cannot be created or destroyed

second law of thermodynamics

every energy transfer or transformation increases the entropy (disorder) of the universe

spontaneous processes

occur without energy input; they can happen quickly or slowly

for a process to occur without energy input, it must increase the entropy of the universe

entropy can decrease in an organism whilst increasing the universe’s total entropy

complex molecules broken down to simple molecules

positive entropy change

spontaneous

catabolic reaction

exergonic reaction-releases free energy and has a negative change in free energy

simple to complex

negative entropy

anabolic reaction

endergonic-requires energy form an outside source

non spontaneous

fermentation

partial degradation of sugars that occurs without O2

aerobic respiration

consumes organic molecules and O2 and yields ATP

anaerobic respiration

consumes compounds other than O2 and yields ATP

cellular respiration

includes both aerobic and anaerobic respiration but often used to refer to aerobic respiration

C₆H₁₂O₆ + 6 O₂ → 6 CO₂ + 6 H₂O + Energy (ATP + heat)

redox reactions

Chemical reactions that transfer electrons between reactants

oxidation

substance loses electrons, is oxidized

reduction

substance gains electrons, the amount of positive charge is reduced

reducing agent

electron donor, giver of negativeness

oxidizing agent

electron receptor/acceptor

3 stages of cellular respiration

glycolysis (breaks down glucose into two molecules of pyruvate)

citric acid cycle (completes the breakdown of glucose)

oxidative phosphorylation (acconti for most of the ATP synthesis

alcohol fermentation

pyruvate is converted to ethanol in 2 steps

the first step releases CO2

2nd step produces ethanol

obligate anaerobes

carry out fermentation or anaerobic reparation and cannot survive in the presence of O2

photosynthesis

6 CO₂ + 12 H₂O + Light energy → C₆H₁₂O₆ + 6 O₂ + 6 H₂O

photosynthesis consists of

light reactions

Calvin cycle

The light reactions (thylakoids)

spilt H2O

release O2

reduce the electron acceptor NADP to NADPH

generate ATP from ADP by photophosphorylation

pigments

substances that absorb visible light

why are plants green?

because chlorophyll (pigment in plant leaves) reflects and transmits green light, but absorbs the other colors

photosystem

consists of reaction-center complex (type of protein complex) surrounded by light-harvesting complexes

light-harvesting complexes

pigment molecules bound to proteins, transfer the energy of photons to the reaction center

primary electron acceptor

in the reaction center, accepts excited electrons and is reduced as a result

Photosystem II

functions first

photosystem, I

best at absorbing a wavelength of 700 nm

during light reactions, there are 2 possible routes for electron flow

cyclic and linear

linear electron flow

the primary pathway, involves both photosystems and produces ATP and NADPH using light energy

Cyclic Electron Flow

electrons cycle back from ferredoxin to the PS I reaction center

uses only PS I and produces ATP, but not NADPH

no oxygen released

how does Crabon enter and exit the Calvin cycle?

it enters as CO2 and exits as glyceraldehyde 3-phosphate (G3P0

for net synthesis of 1 G3P, the cycle must take place 3 times, fixing 3 molecules of CO2

Calvin cycle has 3 phases

carbon fixation (catalyzed by Rubisco)

reduction

regeneration of the CO2 acceptor (RuBP)

photorespiration

rubisco adds o2 rather than CO2 in the Calvin cycle, producing a 2 carbon compound

consumes O2 and organic fuel and releases CO2 without producing ATP or sugar

C4 plants

minimize the cost of photorespiration by incorporating CO2 into four-carbon compounds

two kinds of leaves in C4 plants

bundle-sheath cells are arranged in tightly packed sheaths around the veins of the leaf

mesophyll cells are loosely packed between the bundle sheath and the leaf surface

sugar production in C4 plants occurs in a 3-step process

1-the production of the four carbon precursors catalyzed by the enzyme PEP carboxylase in the mesophyll cells

2-these four-carbon compounds are exported to bundle-sheath cells

3-within the bundle sheath cells, they release CO2 that is then used in the Calvin cycle

Crassulacean acid metabolism (CAM) plants

open their stomata ar night, incorporating CO2 into organic acids

stomata closed during day, and CO2 is released from organic acids and used in the Calvin cycle