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Human
Anatomy & Physiology I
Chapter 4
Cell Metabolism
4-1
Chapter 4
Cellular Metabolism
________________ – all chemical reactions that occur in
the body
Two types of metabolic reactions
Anabolism
• _______ molecules
are made
• ________________
_____________
• larger molecules are
broken down
• _____________
4-2
Anabolism
Anabolism provides the substances needed for cellular
growth and repair
____________________
• type of anabolic process
• used to make polysaccharides, triglycerides, and
proteins
• _________________
4-3
Anabolism
4-4
Catabolism
Catabolism breaks down larger molecules into smaller ones
Hydrolysis
• ___________________
• used to decompose ____________, lipids, and proteins
• water is used
• reverse of dehydration synthesis
4-5
Catabolism
4-6
Control of Metabolic Reactions
____________
• control rates of metabolic reactions
• lower activation energy needed to start reactions
• globular proteins with specific shapes
• not consumed in chemical reactions
• _____________
• shape of _________ determines substrate
4-7
Control of Metabolic Reactions
Metabolic pathways
• series of enzyme-controlled reactions leading to formation of a
product
• each new substrate is the product of the previous reaction
Enzyme names commonly
• reflect the substrate
• have the suffix – _____
• ________e, lactase, protease, ________
4-8
Control of Metabolic Reactions
Cofactors
• make some enzymes
active
• _________________
Coenzymes
• organic molecules
that act as cofactors
• ____________
Factors that alter enzymes
• ________
• ___________
• _________
• chemicals
• changes in ____
4-9
Energy for Metabolic Reactions
Energy
• ____________________________________
• heat, light, sound, electricity, mechanical energy, chemical
energy
• ________________________________
• involved in all metabolic reactions
Release of chemical energy
• most metabolic processes depend on chemical energy
• ___________ of glucose generates chemical energy
• ________________ releases chemical energy from molecules
and makes it available for cellular use
4-10
Cellular Respiration
Occurs in three series of reactions
1. ___________
2. ______________
3. Electron transport chain
Produces
• ______________
• ________
• ATP (chemical energy)
• heat
Includes
• anaerobic reactions (without O2) - produce little ATP
• aerobic reactions (requires O2) - produce most ATP
4-11
ATP Molecules
• each ATP molecule has three parts:
• ____________________
• a ________________
• three phosphate molecules in a chain
• third phosphate attached by high-energy bond
• when the bond is broken, energy is transferred
• when the bond is broken, ATP becomes ADP
• _____________________________________
• phosphorylation requires energy released from cellular respiration
4-12
Glycolysis
• series of ten reactions
• breaks down glucose into ________________
• occurs in cytosol
• ________________________ respiration
• yields two ATP molecules per glucose
Summarized by three main events
1. _________________
2. ______________
3. production of NADH and ATP
4-13
Glycolysis
Event 1 - ______________
• two phosphates
added to glucose
• requires ATP
Event 2 – _______(cleavage)
• _-carbon glucose split
into ______________
molecules
4-14
Glycolysis
Event 3 – ________________ and
______
• hydrogen atoms are released
• hydrogen atoms bind to _____ to
produce _______
• NADH delivers hydrogen atoms
to electron transport chain if
oxygen is available
• ____ is phosphorylated to
become _______
• two molecules of _________ are
produced
4-15
Anaerobic Reactions
If oxygen is not available • electron transport
chain cannot accept
_______
• _________ is converted
to lactic acid
• glycolysis is inhibited
• ATP production
declines
4-16
Aerobic Reactions
If oxygen is available –
• pyruvic acid is used
to produce _________
citric acid cycle begins
• electron transport
chain functions
• carbon dioxide and
water are formed
• __ molecules of ATP
produced per glucose
molecule
4-17
Citric Acid Cycle
• begins when acetyl CoA
combines with _________
acid to produce citric acid
• citric acid is changed into
oxaloacetic acid through a
series of reactions
• cycle repeats as long as
pyruvic acid and oxygen are
available
• for each citric acid
molecule:
• one ATP is produced
• eight hydrogen atoms
are transferred to NAD+
and FAD
• two CO2 produced
4-18
Electron Transport Chain
• NADH and FADH2 carry electrons to the ETC
• ETC series of electron carriers located in cristae of
mitochondria
• energy from electrons transferred to ________________
• ATP synthase catalyzes the phosphorylation of ADP to ATP
• water is formed
4-19
Summary of Cellular
Respiration
4-20
Summary of Catabolism of
Proteins, Carbohydrates, and Fats
4-21
Carbohydrate Storage
Excess glucose stored as
• _________ (primarily by liver and muscle cells)
• fat
• converted to amino acids
4-22
Regulation of Metabolic
Pathways
• limited number of regulatory enzymes
• _________________
4-23
Nucleic Acids and
Protein Synthesis
_______________ – instructs cells how to construct
proteins; stored in DNA
Gene – segment of DNA that codes for one protein
Genome – ________________
_________ – method used to translate a sequence of
nucleotides of DNA into a sequence of amino acids
4-24
Structure of DNA
• two polynucleotide
chains
• hydrogen bonds hold
nitrogenous bases
together
• bases pair specifically
(____________)
• forms a helix
• DNA wrapped about
histones forms
chromosomes
4-25
RNA Molecules
Messenger RNA (mRNA) • delivers genetic information
from nucleus to the cytoplasm
• single polynucleotide chain
• formed beside a strand of DNA
• ______________ are
complementary to DNA
nucleotides (exception – no
thymine in RNA; replaced with
uracil)
• making of mRNA is
transcription
4-26
RNA Molecules
_______________________ • carries amino acids to mRNA
• carries anticodon to mRNA
• _________ a codon of mRNA into an amino acid
Ribosomal RNA (rRNA) –
• provides structure and enzyme activity for ribosomes
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Protein Synthesis
4-28
Protein Synthesis
4-29
DNA Replication
• hydrogen bonds break
between bases
• double strands unwind
and pull apart
• new nucleotides pair
with exposed bases
• controlled by _____
polymerase
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Mutations
Mutations – _________________
information
Result when
• __________________
deleted
• bases are changed
May or may not change the
protein
Repair enzymes correct
mutations
4-31
Clinical Application
________________
PKU
• enzyme that breaks down the _____________________
is missing
• build up of phenylalanine causes mental retardation
• treated by diets very low in phenylalanine
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