Download Cellular Metabolism

Introduction
Cellular Metabolism
Chapter 4
Metabolism is many chemical reactionss
Metabolism breaks down nutrients and
releases energy= catabolism
„ Metabolism builds molecules to store
energy= anabolism
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Anabolism
Anabolism
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Peptide bonds link amino acids
Eg. Dehydration synthesis
Enzymes regulate all chemical
reactions in cells
Catabolism
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Breaking larger molecules into smaller ones
Eg: hydrolysis
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When a product is made
Which product is made
How much product is made
How quickly the product is made
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Enzyme Characteristics
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Catalysts
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Reactions occur 1,000,000 times faster with
enzymes
Not part of reaction
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Enzyme and Substrate
Not changed or affected by reaction
Used over and over
Made of protein
End in “-ase”
DNA (Deoxyribonucleic acid)
Blue prints of enzymes
Blueprints of proteins
„ Deciphering genes, chromosomes, DNA.
DNA
Genetic code
This code instructs cells how to synthesize
enzymes and protein molecules.
„ Portion of DNA with information for
making a particular protein is a GENE
„ All of the DNA in a cell makes up the
genome
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How do they relate?
Human Genome
2% of the human genome encodes protein
Rest controls when and where genes are
used
„ Also many repetitive DNA sequences- we
don’t know what for.
„ Completed in 2003
DNA replication
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During cell division, DNA must be copied
New cell receives a copy of the DNA
Bonds between base pairs of the double
strands break
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Review of Nucleic Acids
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Nitrogen bases
Contain C, H, O, N, P
Function: energy carriers
„ ATP
Function: genetic systems
„ DNA, RNA
„ Determine what
proteins are made
Structure: nucleotides
bonded together to form long
chains
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RNA – 4 possible
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Adenine - A
Cytosine - C
Guanine - G
Uracil – U
DNA – 4 possible
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Adenine – A
Cytosine – C
Guanine – G
Thymine - T
Base Pairs
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Nitrogen bases of the
nucleotides occur in pairs
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4 nitrogen bases in DNA
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Hold the 2 strands of DNA together
Bonding is specific
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A–T
T–A
C–G
G–C
DNA Replication
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DNA separates
Each chain links itself to
DNA nitrogen bases
Forms two new strands
of DNA
Sequence determines the order
of amino acids in a protein
Protein Synthesis - Transcription
Protein Synthesis
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HOW TO MAKE A PROTEIN?
„ Need to find the correct order of amino
acids to build a protein.
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DNA separates
Each chain links itself to
RNA nitrogen bases
(Transcription)
4 nitrogen bases in RNA
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Bonding is specific
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Forms a single strand of
RNA
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A–U
U–A
C–G
G–C
mRNA
tRNA
Mutations may occur
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Protein Synthesis - Translation
RNA
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Messenger RNA- carries the genes’
message out of the nucleus
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Transfer RNA- correctly aligns amino
acids to form proteins
RNA “translates” genes’
messages
RNA moves out into
cytoplasm
„ mRNA binds to a
ribosome
„ tRNA binds to specific
amino acids
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Summary of Replication,
Transcription, Translation
Carries them to mRNA
Amino acids bond
together
„ Form a protein
Metabolism in Cells requires
Energy - ATP
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Aerobic respiration uses oxygen
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Glucose enters cells
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Broken into smaller sugar molecules
Occurs in cytoplasm
„ Yields 2 ATP
These smaller sugar molecules are further metabolized
„ Enter mitochondria
„ Series of chemical reactions yields 34 ATP
Metabolism in Body Cells
(cont’d)
Aerobic Respiration
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Anaerobic respiration occurs when oxygen is
not present
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Glucose enters cells
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Broken into smaller sugar molecules in cytoplasm
„ Yields 2 ATP
Fats and proteins are also used to make ATP
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