Test 2 notes in depth

CHAPTER 5 — THE WORKING CELL

The Working Cell

Basic Energy Concepts

energy = the capacity to do work or produce

change. It exists in various forms.

Kinetic energy – the energy an object

possesses due to its motion.

Potental energy – the energy stored in an

object due to its position or configuration.

energy conservation– energy cannot be

created or destroyed but can only be transformed from one

form to another.

A lot of energy is converted into heat. Heat is a type

of kinetic energy contained in the random motion

of atoms and molecules.

All transformations of energy generate heat. Heat is

often difficult to harness for useful work.

entropy = is a measure of the

disorder or randomness in a system. Every time

energy is converted from one form to another entropy or

disorder increases.

Living things use chemical energy to fight

disorder. Chemical energy is a form of potential energy which

is used to do work.

carbon dioxide

water

oxygen

heat

gasoline work

carbon dioxide

oxygen water

food heat

work

cellular

Respiration

carbohydrates

Fats

Other food molecules

Cellular Respiration

Cannot be used

directly to do work

ATP

• ATP = adenosine triphosphate.

• ATP supplies the energy for chemical reactions

and cell work. It is generated by catabolic

reactions (breaking down food).

• ATP is like a rechargeable battery .

Enzymes and Metabolism

Metabolism = a

term used to represent all an

organisms chemical reactions.

Energy Energy

catabolic (release energy)

• This metabolic pathway releases energy

by breaking down complex molecules.

• Exergonic reaction

➢ Fermentation

➢ Glycolysis

➢ citric acid cycle

➢ Electron transport chain

Anabolic pathways

(use energy)

• This metabolic pathway consumes

energy to build complex

molecules.

• Endergonic reaction

➢ Lift weights…..eat amino

acids….build large muscles

enzymes

• An enzyme is a catalytic protein =

changes the rate of a chemical reaction without being

consumes .

• Without enzymes, chemical reactions would be too

slow to keep an organism alive.

Enzymes reduce the

activation

Energy (Ea) needed for a

Chemical reaction to occur.

Enzymes are specific

• substrate = the reactant an enzyme acts

on.

• active site= the location on the enzyme

that the substrate fits into.

Substrate

Active site

Apheloria virginensis

Apheloria tigana

Catalase

What affects an enzymes activity?

1. temperature

• Too hot or too cold, enzyme doesn’t work at

optimal level.

2. pH

3. Inhibitors

Competitive inhibitor examples

Antabuse

Ethanol breaks down into acetaldehyde. Acetaldehyde breaks

down to acetic acid by an enzyme called aldehyde oxidase.

Antabuse competes with acetaldehyde for this enzyme thus

causing acetaldehyde to accumulate. This causes nausea and

vomiting.

methanol

Consumed methanol breaks down to formaldehyde and then to

formic acid. Converting methanol to formaldehyde is done by

alcohol dehydrogenase. Formic acid attacks the optic nerve

and causes blindness. Methanol poisoning is treated by

ingesting ethanol. Ethanol acts like a competitive inhibitor.

anti freeze

Uses same enzyme as above. When ingested it breaks down

into glycolaldehyde and glycolic acid. These chemicals cause

cerebral edema and kidney failure. Treatment for poisoning is

to drink ethanol.

Membrane Structure and Function

How do substances enter and exit the cell?

• The cell membrane is selectively permable

• It is permeable to hydrophobic

substances but not to hydrophilic

substances.

• Transport proteins are used to bring

in hydrophilic substances.

passive transport

• Cell does not use energy

1. Diffusion

• When a population of molecules moves from an

area of higher concentration to an area

of lower concentration.

CO2, O2, and hydrocarbons

2. osmosis (facilitated diffusion)

• The diffusion of water across c.m.

• Water moves from an area of lower solute

to an area of higher solute.

• Is facilitated by protein channels created by

aquaporins.

Solutions

• When comparing two aqueous solutions, 3 states can

be observed.

isotonic hypotonic hypertonic

•Two solutions •The solution with •The solution

which each low solute with high

have equal solute concentration solute

concentrations concentration

•Greater amount

•Equal amounts of water •Less amount

of water of water

osmoregulation = control of water

balance by organisms

3. transport

• Describes when a cell uses its own energy to pump an ion

or molecule across the cell membrane

againstits concentration gradient.

• This transport is performed by membrane protines

(energy supplied by atp).

Sodium-Potassium pump

Transport of Large Molecules

1. exocytosis = the releasing of

molecules outside the cell

2. endocytosis = the bringing in of

molecules.

Types

A. Phagocytosis (cellular eating)

B. pinocytosis (cellular drinking)

Cell wall

• A structure covering the plasma membrane in

plants, fungi, some protists, and

prokaryotes

• In plant cells, composed of microfibrils made of

cellulose-.

• Helps maintain plant cell shape

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CHAPTER 6 — CELLULAR RESPIRATION

Cellular Respiration

Cellular respiration

• Overview

• Converts ADP to ATP. ATP used for cellular work

✓active transport

✓Movement

✓cell signaling

✓Activation of enzymes

✓Changing molecules for metabolism

ATP is able to transfer a phosphate group

to proteins or other molecules. This is called

phosphorylation.

A protein/molecule receiving a phosphate group is

energized. Often the phosphate group

changes the shape of protein/molecule thus changing

its function.

The energy to replenish ATP comes from

the removal of H and electrons from

fuel sources.

oxidized reduced

dehydrogenase 2e- 1 proton

Cellular respiration occurs in 3 stages

1. Glycolysis

2. Citric acid

cycle(Krebs Cycle)

3. electron transport

Glycolysis and the citric acid cycle are

catabolic pathways that

decompose glucose and

other organic fuels.

GLYCOLYSIS

• Means “splitting of sugar"

• Is a process that occurs in the

cytosol of all organisms.

• It occurs in 10 steps.

Summary of Glycolysis

1 Glucose molecule decomposes to:

• 2 pyruvic acid

• net 2 atp(4 ATP made

but 2 ATP invested initially).

• 2 NADH (Goes to electron

transport chain carrying high energy

electrons)

citric acid cycle

• Occurs only in aerobic

organisms

• Occurs in matrix of

mitochondria

• Completes the oxidation of

glucose

Mitochondrion Practice Drawing

Processing pyruvic acid so it can enter the

citric acid cycle.

Summary of Preparing Pyruvate

2 Pyruvate prepared to enter citric acid

cycle produce:

• 2 co2 (waste product)

• 2 nadh (are sent to the

electron transport chain)

Summary of citric acid cycle

2 pyruvic acids enters citric acid cycle and

produce:

• 6 nadh (sent to electron transport

chain)

• 4 co2 (waste product)

• 2 FADH2 (sent to electrons

transport chain)

• 2 atp

electron trainsport chain

• Electrons are dropped off at proteins embedded in the inner membrane

of mitochondrion

• At the electrons are passed from protein to protein energy is released by the electron

to do work.

• Each protein that the electrons pass from open to allow

hydrogen ions to be pumped from the matrix to the

innermembrane space.

• Hydrogen ion concentration builds upin this space.

• At the last protein, in the three protein sequence, oxygen picks up the

electrons along with 2 hydrogen ions and forms water.

• As hydrogen ions move through a protein called atp synthase, ADP

joins with phosphate and makes ATP.

ETC Practice Drawing

anaerobe = an

organism that does

notuse oxygen as final

electron acceptor (may use sulphur,

nitrate, or sulfate).

aerobe = an organism

that does useoxygen as

final electron acceptor.

Final Summary of decomposition of 1 glucose molecule

Glycolysis 2ATP

Citric acid cycle 2ATP

ETC 10 NADH = 25 ATP

2 FADH2 = 3 ATP

TOTAL = 32 ATP

What happens if you use ATP faster than you deliver

oxygen to the cells?

• Oxygen is not longer available to pick up

electrons.

• Electrons back upin the proteins in the

inner membrane of the mitochondrion.

• The electron transport chain stops.

• reduced nadh molecules cannot

drop off electrons.

• oxidized nadmolecules become

unavailable.

Latic acid fermentation

• Allows your muscles to generate ATP for a short period

to keep the muscles working.

• Eventually the muscles will stop working due to the build up of

latic acid .

• Lactic acid is taken out of the muscle cells and put in the bloodstream

and taken to the liver to be converted back into pyruvic

acid .

• Some foods like yogurt, cheese, and sour cream are made by making

microbes undergo fermentation. They produce lactic acid which

converts milk into different food products.

alcohol fermentation

• This process takes place in some microbes like

yeast .

• In alcohol fermentation we can make food products

like bread, beer, and wine. (Bread rises from carbon

dioxide bubbles collecting in the bread dough).

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CHAPTER 8 — CELLULAR REPRODUCTION

Chapter 8 Cellular Reproduction

Functions of Cell Division

1. Reproduction

2.Reproduction

Growth

Repair

3.Growth

Repair

prokaryotes eukaryotes

• Cells reproduce by • Cells divide by

binary mitosis

fission (Multiple noncircular

(bacterium chromosomes

replicates 1 circular replicated, n.m.

DNA molecule and breakdown, and

then cell pinches highly coordinated

into 2. division of

chromosomes and

organelles).

DNA Packing

• Chromosomes are made

of DNA and

proteins .

• Before cells can divide a

complete copy of the

DNA must be

respirated.

• Special proteins called

histone

proteins – help to coil and

pack DNA for cell

division.

Overview of Mitotic Cell Cycle

Interphase

• Divided into 3 stages.

G1 phase

• Cell enlarges and grows more organells

• During this phase cells decide to divide or become

overspecialized or die

s phase

• During this phase all the chromosomes are

duplicated

• DNA goes from being single stranded to being

double stranded. centromes connect

sister chromatids.

G2 phase

• More growth and final preparations for division.

mitotic phase

• mitosis – during this

phase the chromosomes are evenly

divided and two daughter nuclei form.

• Cytokinesis – all the

organelles (the cytoplasm) are divided

into 2 cells as the cells pinch apart.

4 Stages of Mitosis

1. Prophase

• DNA coils into distinct

chromosomes

• Nuculear memebrane breaks up.

• Mitotic spindle tracks

form

2. metaphase

• Chromosomes line up in the middle of

the cell.

3. anaphase

• Sister chromatids separate and move

to opposite sides of the cell.

• The cell elongates

4. telephase

• Nuclear membranes reform

• chromosomes begin to uncoil

• spindle disassembles

Cells can undergo

between 40-

60 cell

divisions at which

point the DNA

shortens and wears

out.

Cytokinesis

Animal Plant

What controls the cell cycle?

G1 Checkpoint (receive signal go to S phase)

G2 Checkpoint

M Checkpoint

When cells don’t respond to cell cycle controls it

results in uncontrolled cell division.

* Results in a Tumor

2 Types of Tumors

1. benign

• Mass of cells that uncontrollably proliferate

but stay together.

• Mass can be removed

2. Malignant

• Uncontrolled cell growth invades

surrounding tissue

• metastasis = spread of malignant

cancer cells to distant locations.

• Cancer is treated with radiation

(destroys DNA in cancer cells) and/or

chemotherapyy (destroys all

actively dividing cells…blood cells, lining of

intestine, hair cells, and cancer cells)

meiosis

(Reduction Division)

2 Major types of

Reproduction

1. asexual

reproduction

• Clone of parent produced

(genetically

identical)

• No varation in

offspring

2. sexual

reproduction

• 2 separate

parents give rise

to offspring

• great

variation due to

new

combinations of

genes.

Humans

46 Total Chromosomes

• 22 pairs of autosomes

(chromosomes other than sex chromosomes)

• 1 pair of sex chromosomes (xx = female

and xy = male).

• Zygote stage to adult 2n (diploid) 2N =

• Gametes (sex cells) 1n (haploid) N =

Phases of Meiosis

interphase

• Similar to mitosis interphase

• All chromosomes replicated (duplicated)

prophase 1

• homologous chromosomes

(chromosomes that have the same length,

centromere position, and same genes) pair

up.

• Homologous chromosomes may trade DNA

segments (this is called crossing over)

• Nuclear membrane disassembles and spindle forms

Metaphase 1

• Homologous pairs line up at metaphase plate.

anaphase 1

• Homologous pairs separate.

• Sister chromatids stay attached.

telophase 1 and cytokensis

• Homologous pairs each move to opposite poles.

• Haploid cell (N = 23) At this stage each

chromosome is made of two sister chromatids.

Prophase 2

• Spindle reforms.

• Chromosomes move toward metaphase plate.

metaphase 2

• Chromosomes line up at metaphase plate.

anaphase 2

• Sister chromatids separate.

telophase 2 and cytokinesis

• 4 daughter cells formed (haploid

cells)

• oogenesis = makes 1 ovum and 2

or 3 polar bodies.

• Spermatogenesis = makes

4 sperm cells

Meiosis and sexual life cycles are generators of

genetic variation.

1. Independent assortment of chromosomes (the way

homologous chromosomes pair up is random.

2. crossing over

• DNA segments that are traded between

homologous pairs in prophase 1

mixes the genes that came from mother and father.

3. Random fertilization

These generators of variation allows organisms to

adapt and evolve over time.

GENETIC DISORDERS

• Can be caused by physical or chemical damage, or

errors that alter chromosomes in sperm/egg

Alterations of chromosome number

nondisjunction= the improper separation of a pair of

homologous chromosomes in meiosis.

1. Aneuploidy = extra or less copies of chromosomes

• Trisomy (2N + 1) ex. Down

syndrome (extra 21) and Klinefelter (XXY)

• Monosomy (2N – 1) ex. Turner syndrome (X)

2. Polyploidy = having extra sets of

chromosomes

• triploid (3N)

• tetraploid (4N)

Alterations of Chromosome Structure

1. Deletion = fragment of

chromosome lost (ex Cri Du Chat)

2. duplication = extra

fragment

3. Inversion = reversal of a

segment

4. translocation = movement

of 1 segment to another location