BIOL1020 Exam 2 -- Riggs

3 basic requirements of a cell

membrane is present, stores and transmits information (DNA), has energy

photoroph

gets energy from light

chemotroph

gets energy from chemicals

autotroph

gets carbon from inorganic carbon sources (make its own)

heterotroph

gets carbon from organic carbon sources (find it, ex by eating it)

metabolism

ALL chemical reactions happening in a cell

anabolism

small molecules built to be bigger molecules, requires energy input, uses ATP

catabolism

breaks large molecules down to smaller, releases energy, makes ATP (usually in form of heat)

ATP

cells main energy source, Adenosine Triphosphate, Adenine + Ribose + 3 phosphate groups

Potential Energy

stored energy, based on position or structure

kinetic energy

energy in action

what energy is used for moving molecules? electrons? photons?

thermal, electricity, light

Chemical potential energy

energy stored in bonds

Lower potential energy

strong bonds

higher potential energy

weak bonds

energy chain

food > chemical energy > ATP > cellular work

First Law of Thermodynamics

energy cannot be created or destroyed, energy is released as heat or light, energy is trnasformed not created

second law of thermodynamics

energy transformations are not 100% efficient, energy becomes less available down the order of work

entropy

degree of disorder/spontaneity in the universe, as energy available for work decreases ______ increases

a chemical reaction ____ atoms

rearranges

bonds between atoms

what changes during chemical reactions

direction of a chemical equation…

depends on the concentrations of the subtances

Gibbs Free Energy

the energy available to do work (ΔG)

Endergonic

ΔG is positive, energy is being put IN, products have more free energy than reactants

Exergonic

ΔG is negative, energy is leaving, reactancts have more free energy than products

cytoskeleton

a network of fibers that organizes and supports the cell, cell structure support and transportation

parts of cytoskeleton

microtubules, intermediate filaments, microfilaments

Microtubules

movement and division, thickest part of cytoskeleton, cilia and flagella, moves vesicles around the cell

centrosome

microtubules grow here and are organized here, has 9 triplets of microtubules

in animal cells the _____ contains a pair of centrioles

cells with cilia/flagella

paramecium, sperm, airway epithelial cells

Intermediate Filaments

support the cell shape, diameter is about 8-12nm, hold organelles in place, more permanent than the others

microfilaments

made of actin, about 7nm in diameter

maintain cell shape, resist pulling forces, help cells move, form the core of the microvilli, help with muscle contraction

cortex

microfilaments form a 3D network called the _____

located just inside the plasma membrane

actin

microfilaments

myosin

motor protein

actin + myosin = _______

movement

amoeba movement, neuron growth, muscle contraction

muscle cells

Cilia v Flagella

______: shorter, usually many present, move back and forth, move fluid material across a cell OR move the cell, in airway cells

______: longer, usually few but often 1 present, whipping movement, usually move the cell, found in sperm cells

Dynein

makes cilia/flagella bend, arms grab > move > release, interact with microtubules, drives movement

Plant Cells : _____ / Animal Cells : ______

cell wall, extracellular matrix (ECM)

cell wall

provides protection, shape, and prevents excess water uptake. found in plants, fungi, prokaryotes, some protists

mainly cellulose

layers of plant cell wall

primary: thin and flexible

secondary: more cells, located between plasma and primary

middle lamella: between primary walls of neighboring plants cells, helps hold cells together

plasma membrane: inside the cell wall

Extracellular Matrix

outside of the cells

collagen, proteoglycans, fibronectin

integrins

ecm interacts with these receptor proteins called ______

Functions of ECM

support, adhesion, movement, regulation, gene expresson

Proteoglycans

part of ECM, made of protein core + glycosaminoglycan (GAG) side cahins

made and secreted by cells

Cell Junctions

1. plasmodesmata

2. tight junctions

3. desmosomes

4. gap junction

Plasmodesmata

found in plants

channels between the cells

tight junction

membranes of neighboring cell walls pressed together, prevent leakage of extracellular fluid, animal cells

desmosomes

animal cells, anchors that fasten cells together into strong sheets

gap junction

animal cells, provide cytoplasmic channels between adjacent cells

cellular respiration

uses carbs, lipids, and proteins to convert energy to ATP

four stages of cellular respiration

1. glycolysis

2. pyruvate oxidation

3. citric acid cycler (aka Krebs or TCA)

4. oxidative phosphorylation

electron carriers

NADH and FADH2

carry high energy electrons to electron transport chain

produces in the first 3 stages of cellular respiration

Substrate level phosphorylation

ATP made directly during a chemical reaction that involves a substrate, phosphate is transferred to ADP that makes ATP

oxidative phosphorylation

ATP is made using the electron transport chain and ATP synthase

takes place at mitochondrial membrane

produces large amount of ATP through electron transport chain

Oxidation

electrons are lost

NAD+ —> NADH

glucose is ______ to CO2 in cellular respiration

Reduction

electrons are gained

NAD+ —> NADH

oxygen is ______ to water during cellular respiration

NADH and FADH2

electron carriers

high potnetial energy

high energy electrons

glycolysis

first stage of cellular respiration

occurs in the cytoplasm

does not require oxygen

glucose —> pyruvate

3 phases of glycolysis

1. preparatory phase

2. cleavage phase

3. payoff phase

preparatory phase

energy is consumed

a phosphate group is added

phosphate group carries energy

glucose is now phophorylated

(INVEST energy first)

cleavage phase

glucose is split into TWO

payoff phase

energy produced

get the energy back and make extra energy carriers

result of glycolysis

4 ATP produced but 2 used, 2 Net ATP

2 Net NADH

pyruvate oxidation, 2

pyruvate —> AcetylCoA

mitochondrial matrix

1 glucose made into ____ pyruvate after glycolysis

carbon is removed from pyruvate and exits as CO2, electrons transferred to NAD+, producing NADH

everything is 2x as much as glucose

products from one glucose

2 pyruvate —> 2 acetylCoA + 2 CO2 + 2 NADH

Citric Acid Cycle

happens in the mitochondrial matrix

oxaloacetate —> ____ —> oxaloacetate

finishes oxidizing the carbon molecules to capture all energy

products of citric acid cycle

CO2 (exits twice)

6 NADH

2 FADH2
2 ATP

citric acid cycle steps

1. acetyle co a enters

2. carbon is released as CO2

3. electron carriers produces (NAD+ —> NADH & FAD —>FADH2)

4. small amount of ATP produced through substrate level phosphorylation

Pyruvate oxidation (simple)

• What? Acetyl-CoA, NADH, CO₂

• How? Pyruvate is oxidized

• Where? Mitochondrial matrix

citric acid cycle (simple)

• What? NADH, FADH₂, ATP, CO₂

• How? Acetyl-CoA is oxidized

• Where? Mitochondrial matrix

oxidative phosphorylation

• What? Lots of ATP

• How? ETC creates H⁺ gradient → ATP synthase makes ATP

• Where? Inner mitochondrial membrane

why are plants green?

chlorophyll that reflects green light

autotrophs

producer of the biosphere

use sunlight to make organic molecules (carbon)

chloroplasts

likely evolved from cyanobacteria

site of photosynthesis

chlorophyll is in the _______ of the thykaloid

membrane

photosynthetic electron transport chain is in the ________

thykaloid membrane

_____ is produced as a byproduct when water oxidizes

oxygen

first organisms believed to use water as an electron donor

cyanobacteria

endosymbiotic theory

a cyanobacterium was engulfed by a eukaryotic cell and that is why cells have organelle chloroplast

shorter wavelength - ______ amount of potential energy

longer wavelength - _______ amount of potential energy

higher, lower

visible wavelength

400-700nm

wavelength of light used by photosynthesis

380-750nm

Pigment

any organic molecule able to absorb light

can only absorb light at a specific wavelength

reflects what it is unable to absorb

accessory pigments

able to absorb light from regions of the visible spectrum that are poorly absorbed by chlorophyll

Carotenoids

red, orange, and yellow accessory pigments

anthocyanins

red and blue accessory pigments

Photosystem

reaction center complex surrounded by light harvesting complexes that excite the electron and transfers energy

PSII

P680 (absorbs light at 680nm)

starting point where water donates electrons

PSI

P700 (absorbs light at 700nm)

NADPH end product

Photosynthesis is…

a redox process, reverse direction of electron movement compared to respiration, endergonic

Linear Electron Flow (photosystems)

P680 to P700 to NADPH and ATP

(refer to drawing on paper)

Cyclic Electron Flow (Photosystems)

P700 to ATP

(refer to drawing on paper)