Transcript 1111138443_282429

Chapter 4
CELLULAR METABOLISM AND
REPRODUCTION: MITOSIS AND MEIOSIS
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
Introduction to Cellular Metabolism
• Metabolism: total cellular chemical changes
– Anabolism: process of building up
– Catabolism: process of breaking down
• Calorie: measure of energy contained in
food
• ATP: energy source available to the cell
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
CELLULAR METABOLISM OR BIOCHEMICAL
RESPIRATION
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to a publicly accessible website, in whole or in part.
Glycolysis
• Breakdown of glucose
• Anaerobic or aerobic process
• Final outcome
– 2 pyruvic acid molecules, 2 ATP molecules
(anaerobic), 8 ATP molecules (aerobic)
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
The Krebs Citric Acid Cycle
• Pyruvic Acid > Acetic Acid > Acetyl-CoA
• Acetyl-CoA enters Krebs cycle in
mitochondria
• Final outcome
– 6 CO2, 8 NADH2, 2 FADH2, 2 ATP (GTP)
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
The Electron Transport
(Transfer) System
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Series of reduction/oxidation reactions
Requires O2
Electron carriers
Number of ATP molecules dependent on
electron carrier
• Water is a waste product
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
Summary of ATP Production
• During glycolysis, the citric acid cycle, and
electron transport
• Glycolysis: 8 ATP (aerobic)
• Krebs cycle and electron transport
– 28 ATP + 2 GTP or
– 30 ATP
• 1 glucose molecule yields 38 ATP
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
ANAEROBIC RESPIRATION
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Fermentation
• Yeast breaks down glucose anaerobically
• Pyruvic acid broken down by
decarboxylase
– Forms carbon dioxide and acetaldehyde
• Final products: 2 ATP, CO2, ethyl alcohol
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
Anaerobic Production of ATP by
Muscles
• Pyruvic acid converted to lactic acid
– Accumulation of lactic acid causes fatigue in
muscles
– When oxygen supplied, lactic acid turns back
into pyruvic acid
• 2 ATP produced per glucose molecule
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
PRODUCTION OF ATP FROM GENERAL FOOD
COMPOUNDS
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Production of ATP from General
Food Compounds (cont’d.)
• Carbohydrates fit into cellular furnace at
same level as glucose
– Can be stored in liver or as fat
• Fats digested into fatty acids and glycerol
– Glycerol enters at PGA stage of glycolysis
– Fatty acids enter Krebs citric acid cycle
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
Production of ATP from General
Food Compounds (cont’d.)
• Proteins digested into amino acids
– Enter into Krebs cycle at different stages
• Dependent on chemical structure
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
INTRODUCTION TO CELLULAR REPRODUCTION
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Introduction to Cellular
Reproduction (cont’d.)
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Process of cell duplication
Mitosis: duplication of genetic material
Cytokinesis: duplication of organelles
Meiosis: reduction division only in gonads
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
THE STRUCTURE OF THE DNA MOLECULE
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The History of the Discovery of
DNA
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Friedrich Miescher, 1869: first discovery
P.A. Levine, 1920s: composition
Rosalind Franklin: helical structure
Watson and Crick: three-dimensional
structure
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The Anatomy of the DNA Molecule
• Double helical chain of nucleotides
– Phosphate group
– Five-carbon sugars (deoxyribose)
– Nitrogen-containing base
• Pyrimidines (thymine and cytosine)
• Purines (adenine and guanine)
– Pyrimidines pair with purines
– Chains held together by hydrogen bonds
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
The Anatomy of the DNA
Molecule (cont’d.)
• Gene: sequence of base pairs that codes
for polypeptide or protein
• Human Genome Project
– 3 billion base pairs that code for 30,000 genes
• Duplication of DNA molecule
– Helicase separates at hydrogen bonds
– DNA polymerase adds new nucleotides
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
THE CELL CYCLE
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Introduction
• All reproduction begins at cellular level
• Interphase
– Previously called resting stage
• Mitosis
• Cytokinesis
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to a publicly accessible website, in whole or in part.
Interphase
• Time between divisions
– G1: Primary growth phase
– S: DNA duplication
– G2: Centrioles complete duplication,
mitochondria replicate, chromosomes
condense and coil
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
Mitosis
• Prophase
– Chromosomes become visible as chromatids
joined by centromere
– Two kinetochores at the centromere
– Centrioles move to opposite poles
– Nuclear membrane breaks down
– Microtubules attach kinetochores to spindle
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
Mitosis (cont’d.)
• Metaphase
– Chromatids align at equator of cell
– Centromere divides
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
Mitosis (cont’d.)
• Anaphase
– Divided centromere pulls chromatids to
opposite pole
– Cytokinesis begins
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
Mitosis (cont’d.)
• Telophase
– Chromosomes uncoil and decondense
– Spindle apparatus breaks down
– New nuclear membrane forms
– Cytokinesis nearly complete
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
Animation – Mitosis
• Stop and watch a 3-D presentation of
mitosis.
Click Here to Play Mitosis Animation
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
Cytokinesis
• Animal cells
– Cleavage furrow forms
– Cell is pinched into daughter cells
• Plant cells
– Cell plate forms at equator
– Cell plate becomes new cell wall
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
MEIOSIS: A REDUCTION DIVISION
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to a publicly accessible website, in whole or in part.
Introduction
• Occurs only in the gonads
• Reduces genetic material from diploid to
haploid
• Two divisions resulting in four cells
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
Stages of Meiosis
• 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
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
Stages of Meiosis (cont’d.)
• 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
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
Animation – Meiosis
• Now that you have learned about the stages of meiosis,
watch the meiosis animation for a visual of this process.
Click Here to Play Meiosis Animation
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
GAMETOGENESIS: THE FORMATION OF THE SEX
CELLS
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to a publicly accessible website, in whole or in part.
Gametogenesis: The Formation
of the Sex Cells (cont’d.)
• Spermatogenesis
– Four cells produced
– Develop into sperm
• Oogenesis
– Four cells produced
– Only one becomes functional egg
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
Animation – Cancer
Metastasizing
• Refer to the Common Disease, Disorder or Condition box
on Cancer in your textbook and read about the growth of
cancer cells. Now watch the 3-D Cancer Metastasizing
animation.
Click Here to Play Cancer Metastasizing Animation
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.
Summary
• Discussed how glucose is converted into
ATP in the presence of oxygen
• Discussed how glucose is converted into
ATP in the absence of oxygen
• Described how fats and proteins are
converted into ATP
• Discussed the cell cycle
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted
to a publicly accessible website, in whole or in part.