Anatomy and Physiology Chapter
#4
23 pairs of
chromosomes in
the human nucleus
Genes
Chromosome
Bases
DNA Strand
4.1 Introduction
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Cells require energy and information to
build bodies.
Cells carry out many reactions of
metabolism.
These reactions break down nutrients to
release energy.
Cells carry genetic info.
Enzyme is a special type of protein that
controls each reaction of metabolism.
4.2 Metabolic Reactions
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Metabolic reactions are of two types: in anabolism reactions,
larger molecules are constructed from smaller one.
The process that provides the biochemicals required for cell
growth and repair is anabolism.
In catabolism reactions, larger molecules are broken down.
The reactions of metabolism are often reversible.
Which process requires energy? Anabolism Which releases
energy? Catabolism
The process of joining two molecules by removing water is called
dehydration synthesis. A by-product of dehydration synthesis is
water.
The process of splitting two molecule by adding water is called
hydrolysis. Hydrolysis occurs during digestion.
4.3 Control of Metabolic Reactions
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Enzymes control the rates of all the metabolic
reactions of the cell.
Enzymes are complex molecule (PROTEIN) that
function to lower the activation energy of a reaction
so it may begin and proceed more quickly. Because
they do this, enzymes are called catalysis.
The substances the enzymes act on are called
substrate. Each enzyme is specific. Enzymes
recognize the specific shape of the substrate with
which they react.
4.3 Control of Metabolic Reactions
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Enzymes are needed to promote metabolic
reactions in the body because the temperature in
cells is not high enough to promote the increase in
chemical reaction rates.
Very small quantities of enzymes are needed
because they are not consumed in the metabolic
reaction they facilitate.
Enzymes can be denatured (destroyed) by heat and
radiation, chemicals and extremes of pH, and
electricity.
4.4 Energy for Metabolic Reactions
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The form of energy most often used by the
body's metabolic processes is chemical.
ATP is Adenosine Triphosphate . It stores the
energy for every reaction in the body.
Energy can be mechanical, chemical, and
thermal.
The function of ATP is to store energy in its
terminal phosphate bond.
Cellular Respiration
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Is the process that releases the energy in
the chemical bonds of the energy nutrients
and stores it in molecules of ATP.
It has 3 basic stages, each of which have
several steps and are controlled by many
enzymes.
The first stage does not require oxygen and
so is said to be anaerobic.
The other two stages require oxygen and
therefore are aerobic.
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Stage of Respiration
The first stage of cellular respiration is
anaerobic and occurs in the cytosol.
The anaerobic respiration is called glycolysis.
Where does it take place? cytosol
What chemical does it start with? glucose
What chemical does it end with? Pyruvic acid
Are any ATP’s formed? 2
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Stages of Respiration
The second phase of cellular respiration is
aerobic and occurs in the mitochondria.
aerobic respiration has two stages.
Where do they occur? mitochondria
What are the three end products of this
process? Oxygen, water, and ENERGY
Stage 2 is called citric acid cycle.
Stage 3 is called electron transport chain.
Figure 4.5 pg 77
Cellular Respiration
Respiration
C6H12O6 + 6O2  6CO2 + 6H2O+ ENERGY
4.5 Metabolic Pathways
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Metabolic pathways are a sequence of
enzyme-controlled reactions.
lipids & protein pathways – these two
nutrients can be used to make ATP. Where
they “plug into” the process is going to
depend on how many Carbons are in the
piece the cell is working on. How many
ATPs formed will also depend on this.
Genetic Info
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Genetic information must tell cells how to
position amino acids correctly in polypeptide
chains.
The function of DNA is to direct the activities
of the cell and to direct the synthesis of
protein by the cell.
DNA molecules are replicated during what
phase of the cell cycle? Interphase
4.6 Nucleic Acids (DNA & RNA)
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Deoxyribonucleic acid (DNA) contains the genetic
code needed for the synthesis of each protein
(including enzymes) required by the cell.
The "backbone" of DNA is composed of alternating
nucleotides joined so that phosphate and sugar
portions alternate. The sugar is named deoxyribose.
Name the four bases. Adenine, Thymine, Cytosine,
Guanine
What are the two base complementary pairs of
DNA? A-T & C-G
DNA is double strands and twists to form a double
helix.
The sequence of nucleotides in a DNA molecule
gives the sequence of amino acids for a given
protein.
DNA
4.7 RNA
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What is the sugar in RNA called? ribose
Name the four bases: Adenine, Cytosine, Guanine,
Uracil.
RNA is single-stranded.
There are 3 types of RNA.
Ribosomal RNA (rRNA)- make ribosomes.
Messenger RNA (mRNA) copy and transfer the
genetic information to the cytoplasm where
proteins are manufactured.
Transfer RNA (tRNA) position amino acids along a
stand of mRNA. tRNA join and form a protein
molecule.
RNA
4.7 Protein Synthesis
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Transcription is the transferring of info from
the DNA in the nucleus to the mRNA.
Translation is the converting from the
“language” of nucleic acids to the “language”
of amino acids this occurs in the cytoplasm.
Transcription = DNA → RNA
Translation = RNA → protein
4.7 Protein Synthesis
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mRNA molecules copy part of the DNA code in the
nucleus.
They then travel to the ribosome where protein
synthesis will occur.
They lie across the ribosome and wait for the tRNA
to bring in the appropriate amino acids.
The correct amino acids will be lined up because
the tRNA bases are arranged in anticodon that are
complementary to the codons of the bases of the
mRNA.
The amino acids bond with peptide bonds to each
other to form a protein.
RNA Transcription
4.8 DNA Replication
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Each new cell must be provided with an exact replica of the
parent cell's DNA. When does DNA replication occur? Mitosis
The DNA molecule splits. Nucleotides form complementary pairs
with the original strands.
Each new DNA molecule consists of one parental strand and one
newly synthesized strand of DNA.
What is a mutation? Changes in DNA can be harmful, helpful, or
have no effect.
The occurrence of mutations may be spontaneous or a result of
exposure to ionizing radiation and toxic chemicals
DNA of the parent cell must be replicated accurately so that the
new cell can maintain life functions, build cell parts and
metabolize nutrients.
DNA Replication
Work Cited
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DNA Replication image.
http://www.genelex.com/paternitytesting/paternityslide1.html
DNA image. http://www.tokyo-med.ac.jp/genet/picts/dnaL.jpg
DNA, gene, chromosome image.
http://www.alzheimers.org/unraveling/09.htm
RNA image.
http://library.thinkquest.org/C0123260/basic%20knowledge/imag
es/basic%20knowledge/RNA/structure%20of%20RNA.jpg
RNA transcription image.
http://www.accessexcellence.org/AE/AEPC/NIH/gene03.html
Cellular respiration image.
http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio
%20101/Bio%20101%20Lectures/Cellular%20Respiration/cellul1
3.gif