CH 4 Cellular Metabolism

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Cellular Metabolism and ReproductionMitosis and
Meiosis

• Amanda Bates

By PresenterMedia.com
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CH 4 Summary Layout

• A second line of text could go here

• Introduction to Cellular Metabolism

Item 1

• Glycolysis

Item 2

• The Krebs Citric Acid Cycle

Item 3

• The Electron Transport System

Item 4

• Summary of ATP Production

Item 5
Item 6
Anaerobic Respiration
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Summary Layout cont..
Production of ATP from General Food Compounds
Item 7

• Introduction to Cellular reproduction

Item 8

• The Structure of the DNA Molecule

Item 9

• The Cell Cycle

Item 10

• Meiosis A Reduction Division

Item 11

• Gametogenesis The Formation of the Sex
• Cells

Item 12
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CELLULAR METABOLISM

• An Introduction

• The most common form of chemical energy that
  maintains cellular structure and function is the
  molecule ATP (adenosine triphosphate)
• Metabolism is a general term that describes the
  total chemical changes that occur in cells.
• There are two subcategories anabolism is the
  energy requiring process that builds larger
  molecules by combining smaller molecules, and
  catabolism is the energy-releasing process that
  breaks down larger molecules into smaller ones.
• These cellular metabolic processes are often
  called cellular respiration or cellular
  metabolism.
• ATP is made in a stepwise catabolism
  (decomposition) of food molecules like glucose.
  The chemical energy in food (calories) is
  released and used to put together ADP (adenosine
  diphosphate) and PO4 (phosphate) to make ATP.

Cellular respiration has 3 processes/steps 1.
Glycolysis 2.Krebs citric acid cycle 3.
Electron transport
Chemical equation for cellular respiration is
C6H12O6 6O2 ? 6CO2 6H2O 38 ATP or 36 ATP and 2
GTP
The breakdown of a glucose molecule into
carbon dioxide gas and water is a continuous
process (1) Occasionally referred to as
anaaerobic respiration (w/out oxygen) (2) (3)
Require Oxygen
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Cellular Metabolism or Biochemical Respiration

• GLYCOLYSIS

• The 1st step in the biochemical respiration
  process.
• Glycolysis occurs in the cytoplasm of the cell
  and does not require oxygen.
• We must use two ATP molecules to start glycolysis
  and these must be paid back from our production
  of ATP.
• The main products of glycolysis are fructose
  diphosphate
• which splits into 2 phosphoglyceraldehyde
  molecules
• that oxidize to 2 phosphoglyceric acids,
• which convert to the final product of two pyruvic
  acid molecules.
• When oxygen is present, two hydrogens from each
  of the two phosphoglyceraldehydes go to the
  electron transport system beginning with the
  cofactor NAD. Th is produces six ATP.

Glycolysis produces a total net gain of 8 ATP. In
anaerobic glycolysis in muscle cells in
fermentation only 2 ATP are produced.
Phosphoglyceric acid decomposed to pyruvic acid
makes 4 ATP 2 at start of sequence
net gain of only 2 ATP
An accent, click to edit the text inside.
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Glycolysis

• The Basic Steps

• In summary
• The glycolytic breakdown of one molecule of
  glucose produces 2 pyruvic acid molecules.
• It took 2 ATP to start the sequence and 4 ATP
  were produced.
• However, to pay back the two ATP, our net gain is
  only 2 ATP.
• We also produced 2 NADH2, which are part of the
  electron transport system.
• When oxygen is present, we produce 6 more ATP via
  electron transport.
• Aerobic glycolysis produces 6 plus 2 or 8 ATP
  molecules.
• Anaerobic produces only 2 ATP.
• Final outcome
• 2 pyruvic acid molecules
• -2 ATP molecules (anaerobic)
• -8 ATP molecules (aerobic)

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The Krebs Citric Acid Cycle

• 1. The citric acid cycle is named for the British
  biochemist Sir Hans Krebs who fi rst proposed the
  scheme in 1937.
• 2. The 2 pyruvic acid molecules produced in
  glycolysis are converted to acetic acid and then
  to acetyl-CoA through the action of CoA enzyme.
  Acetyl-CoA now enters the cristae of the
  mitochondria to go through the citric acid cycle.
  
• 3. The major chemical products in the cycle are
  citric acid, alpha-ketogluteric acid, succinic
  acid, malic acid, and oxaloacetic acid.
• 4. Most of the ATP is made by electron transport.
  For each of the 2 pyruvic acid molecules broken
  down, 14 ATP are made via electron transport for
  a total production of 28 ATP. In addition, 2 ATP
  or GTP are produced in the citric acid cycle, for
  a total of 30 ATP or 28 ATP and 2 GTP
• 5. For each pyruvic acid molecule broken down, 3
  CO2 are given off as waste products for a total
  of 6 CO2 molecules produced.

Final outcome 6 CO2, 8 NADH2, 2FADH2, 2 ATP
(GTP)
Acetyle-CoA enters Krebs cycle in mitochondria
Pyruvic Acid gt Acetic Acid gt Acetyl-CoA
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The Krebs Citric Acid Cycle

• And its products

• In summary
• For every pyruvic acid that enters the Krebs
  citric acid cycle
• 3 CO2
• 4 NADH2
• 1 FADH2
• and 1 ATP (GTP) are produced.
• Because 2 pyruvic acids entered the cycle, we
  must multiply all of these products by 2.

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The Electron Transport System

• (Transfer System)

• 1. The electron transport system functions as a
  series of redox (reduction-oxidation) reactions.
• 2. There are several kinds of electron carriers
  in the electron transport system NAD
  (nicotinamide adenine dinucleotide), FAD (favin
  adenine dinucleotide), quinone, and the
  cytochrome system.
• 3. If the system begins with NAD, then 3 ATP are
  produced. If the system begins with FAD, then
  only 2 ATP are produced.
• 4. Oxygen is necessary for respiration because
  oxygen is the ultimate electron acceptor in the
  system.
• 5. When oxygen accepts the electrons from the 2
  hydrogen atoms and the 2 hydrogen protons, water
  (H2O) is produced as a waste product.

Electron carriers Water is a waste product
Series of reduction/oxidation reactions
Requires O2
Number of ATP molecules dependant on electron
carrier
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Electron Transport

• Or Transfer System and ATP production

• In Summary
• When electrons are donated to NAD, 3 ATP units
  are formed during the entire electron transfer.
• However, when the electrons are donated directly
  to FAD
• and NAD is bypassed, only 2 ATP units are formed
  during
• the electron transfer.

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Summary of ATP Production
Summary of ATP Production

• 1. Glycolysis produces a total net gain of 8 ATP.
• 2. The Krebs citric acid cycle produces for each
  of the 2 pyruvic acid molecules 14 ATP via
  electron transport 1 ATP or GTP. Total ATP
  production in the cycle is 28 ATP and 2 GTP or 30
  ATP.
• 3. The 8 ATP from glycolysis and the 30 ATP from
  the citric acid cycle yield a total of 38 ATP
  from each glucose molecule.

• Glycolysis - 8 ATP (aerobic)
• Krebs cycle
• 28 ATP 2 GTP or
• 30 ATP
• 1 glucose molecule yields 38 ATP

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Anaerobic Respiration

• 1. Fermentation-process of yeast cells break down
  glucose in the absence of oxygen.
• This process produces only 2 ATP and is much less
  efficient than glycolysis.
• 2. The other products of fermentation are carbon
  dioxide gas and ethyl alcohol
• causes bread dough to rise
• used in the beer, wine, and liquor industries.
• 3. When we overwork our muscles and cant get
  enough oxygen to the muscle cells, they begin to
  break down glucose in the absence of oxygen.
• The total net gain of ATP is only 2 ATP molecules
  
• pyruvic acid is converted to lactic acid
• 4. The buildup of lactic acid in the muscle cells
  is what causes the fatigue in overworked muscles
  .Our breathing and heartbeat rates accelerate to
  get more O2 to the cells. Eventually, the fatigue
  goes away as lactic acid is converted back to
  pyruvic acid when oxygen again becomes available.

Fermentation 2 ATP, CO2, ethyl alcohol
Muscle fatigue 2 ATP, pyruvic acid converted
to lactic acid
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• How the digestion of proteins fats fits into
  the biochemical respiration process.

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Production of ATP from General Food Compounds

• The cellular furnace that burns food to produce
  ATP consists of glycolysis, the Krebs citric acid
  cycle, and electron transport.
• Carbohydrates enter the furnace at the level of
  glucose in glycolysis
• Fats are digested into glycerol, which feeds into
  the furnace at the phosphoglyceric acid stage of
  glycolysis
• Fatty acids feed into the citric acid cycle
• Proteins are digested into amino acids
• They feed into the furnace at different stages of
  glycolysis and the citric acid cycle based on
  their chemical structure
• Carbohydrates, fats, and proteins are all
  potential sources of cellular energy b/c they can
  all be broken down their chemical energy can be
  converted into another form of chemical energy,
  ATP, which runs the cells machinery.

Carbohydrates provide glucose for glycolysis
Glycolysis, Krebs citric acid cycle, and electron
transport
Fats digested into glycerol Proteins digested
into amino acids
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How a piece of candy gets metabolized to ATP
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Cellular Reproduction

• The double helical chain of nucleotides of a DNA
• molecule

• Cellular reproduction is the process by which a
  single cell duplicates itself
• Mitosis is duplication of the genetic material in
  the nucleus.
• Cytokinesis is the duplication of the organelles
  in the cytoplasm.
• Meiosis is a special kind of reduction division
  that occurs only in the gonads.

S Deoxyribose, P Phosphate, C Cytosine, G
Guanine, A Adenine, T Thymine
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Structure of the DNA Molecule

• History of the Discovery of DNA

• DNA was first discovered in 1869 by a German
  chemist, Friedrich Miescher.
• In the 1920s, P. A. Levine discovered that DNA
  contained phosphates, five-carbon sugars, and
  nitrogen-containing bases.
• A British citizen, Rosalind Franklin, discovered
  the helical structure of DNA via X-ray
  crystallography studies.
• James Watson, an American, and British Francis
  Crick won the 1962 Nobel Prize for working out
  the three-dimensional structure of the molecule.
• The Double Helix by James Watson, opened up whole
  new fields of research for the 20th century
  recombinant DNA, the Human Genome Project, and
  genetic engineering.

Rosalind Franklin helical structure
P.A. Levine 1920s composition
Watson and Crick three-dimensional structure
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• Anatomy of the DNA Molecule

• Double helical chain of nucleotides
• phosphate group
• five-carbon sugars (dexyribose)
• nitrogen-containing base
• Pyrimidines (thymine and cytosine)
• Purines (adenine and guanine)

purine consists of a fused double ring of
nine atoms of carbon and nitrogen. Th ere are
two purines in the molecule adenine and guanine
pyrimidine consists of a single ring of six atoms
of carbon and nitrogen. Th ere are two
pyrimidines in the molecule thymine and cytosine
In the chain of nucleotides, bonds form
between the phosphate group of one nucleotide and
the sugar of the next nucleotide. The base
extends out from the sugar.
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DNA Molecule

• A gene is a sequence of organic nitrogen base
  pairs that codes for a polypetide or protein.
• In our 46 chromosomes there are billions of
  organic base pairs that encode over 30,000 genes.

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The CELL CYCLE

• Illustration of Interphase and the stages of
  mitosis

• -process by which
• a cell divides into 2
• duplicates its
• genetic material
• Interphase
• Mitosis
• Prophase
• Metaphase
• Anaphase
• Telophase
• Cytokinesis

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Stages of the Cell Cycle

• Cell Division

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Interphase

• Time between divisions
• G1 - primary growth phase
• S - DNA duplication
• G2 - centrioles complete duplication,
  mitochondria replicate, chromosomes condense and
  coil
• The major portion of the life of the cell is
  spent in G1.
• During the S phase, the genetic material or
  DNA
• duplicates itself.
• During the G2 phase, mitochondria replicate
  and
• the chromosomes condense and coil. Tubulin is
• synthesized.

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Mitosis 4 stages

• Prophase, Metaphase, Anaphase, Telophase

• The cellular division in the nucleus
• Prophase- duplicated chromosomes shorten, thicken
  and become visible as 2 sister chromatids held
  together in the middle, called the centromere
• 2 kinetochores found at the centromere
• Centrioles moves to opposite poles of the cell
  form spindle and asters in animal cell
• nuclear membrane breaks down the nucleus
  dissapears
• Microtubules attach the kinetochores to the
  spindle.
• Metaphase- sister chromatids align in a circle at
  the equator of the cell held in place by the
  microtubules attached to the kinetochores of the
  centromere
• - The centromere divides

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Mitosis 4 stages

• Prophase, Metaphase, Anaphase, Telophase

• Anaphase- Each divided centromere pulls a sister
  chromatid to an opposite pole
• Cytokinesis begins
• Telophase- chromosomes begin to uncoil
  decondense
• The spindle apparatus breaks down
• A new nuclear membrane forms around the cluster
  of chromosomes a each pole
• Cytokinesis is nearly complete

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Cytokinesis

• In Plant Animal Cells

• Animal Cells- a cleavage furrow forms by pinching
  in of the cell membrane, resulting in 2 daughter
  cells
• Plant Cells- cell plate forms at the equator
  grows outward, effectively dividing the cell in
  2.
• The cell plate becomes a new cell wall.

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Meiosis

• A reduction division of the nuclear material

• Occurs only in the gonads
• Reduces genetic material from 46 (diploid/2N) to
  23 (haploid/N) chromosomes
• Consists of 2 divisions resulting in 4 cells
• 1st meiotic division reduces of chromosomes
  in ½
• 2nd meiotic division corrects their duplicated
  nature

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The stages of Meiosis (I)

• Prophase I - homologous chromosomes pair and
  cross over
• Metaphase I - chromosomes align along equator
• Anaphase I - centromeres pulled to poles
• one member to each pole
• Telophase I - one of each pair is at each pole

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Stages of Meiosis (II)

• Prophase II - spindle forms, centrioles move to
  poles
• Metaphase II - chromosomes line up at equator
• Anaphase II - centromeres divide
• Telophase II
• chromatids at each pole, new nuclear membrane
  forms

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Video clips of

• Mitosis Meiosis

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Gametogenesis

• The Formation of the Sex Cells

• Spermatogenesis
• four cells produced develop into sperm

• Oogenesis
• four cells produced only one becomes functional
  egg

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The sexual cycle

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Comparison

• Mitosis

• Meiosis

• 2 daughter cells with the exact same genetic
  material
• Cellular division for growth maintenance and
  repair.

• 4 daughter cells with ½ the gentetic material
• Cellular division for reproduction

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Picture Page Layout
FAQ
What is the difference between mitosis and
meiosis? Mitosis and meiosis are both forms of
cell division, but there are important
differences between them. Mitosis is cell
division in which a cell duplicates its genetic
material. The newly formed daughter cells are
identical to their parent. This process occurs
constantly throughout the body. Meiosis, which
is also known as reduction division, occurs only
in the gonads and produces the genetic material
for the sex cells. After meiosis, each sex cell
contains only half the original amount of genetic
material. When a sperm and an ovum unite, each
contributes half of the newly formed genetic
package. How is DNA duplicated during cell
division? It all begins, and ends, with DNA in
the form of a double helix. You may want to
visualize a double helix as two pieces of string
twisted together. A double helix contains two
identical strands of nucleotides that are held
together by a hydrogen bond. During the
duplication process, the hydrogen bond is
released, the strands separate, and the helix
unwinds. While this is happening, nucleotides are
creating an identical copy of each divided
strand. One newly created strand joins each of
the separated strands. As they come together,
they twist and form a double helix that is
identical to the original. Which is more
efficient glycolysis or the anaerobic production
of ATP? Both processes produce adenosine
triphosphate (ATP), which contains the chemical
energy that a cell can use. Of the two processes,
glycolysis is by far the most efficient. In
glycolysis, there is a net gain of eight ATP
molecules. In the anaerobic process, only two
ATP molecules are produced. Why is glycolysis
necessary? Cells require energy to function, and
the body meets this need by delivering molecules
of glucose (blood sugar). Cells cannot use
glucose in this form, however. Glycolysis is the
process that converts glucose to pyruvic acid or
lactic acid and yields energy as ATP
molecules. The names of the stages of mitosis and
meiosis sound a lot alike. Are there any tips or
tricks for distinguishing them? Here is a tip to
help you remember the difference. Mitosis
consists of four phases prophase, metaphase,
anaphase, and telophase. Note that these names
have no numbers. Meiosis consists of two
separate divisions with four phases in each. The
first division consists of prophase I, metaphase
I, anaphase I, and telophase I. The second
division consists of prophase II, metaphase II,
anaphase II, and telophase II. So, in meiosis, a
name and a number are used to indicate which
division and phase are taking place.

• Picture Caption Here

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