Living Environment Review
Breaking down and building up
Hydrolysis digestion: process of breaking large
organic molecules such as proteins and starches
into smaller molecules.
Large molecules must be hydrolyzed before they
enter a cell
Synthesis: building large organic molecules from
small ones
Cells often use food molecules to build larger
molecules they need
Dehydration Synthesis
What are the 4 classes of organic
molecules?
1.Carbohydrates
2.Lipids
3.Proteins
4.Nucleic Acids
Carbohydrates
• Monosaccharide = simple sugar
– Examples include glucose, fructose, and ribose.
• Disaccharide = double sugar
– Examples include sucrose, lactose, and maltose.
• Polysaccharide = complex sugar
– Examples include storage polysaccharides such as
starch and glycogen, and structural polysaccharides
such as cellulose and chitin.
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Lipids
•
•
•
•
Fats and oils
Many different types
Are insoluble in water
Used for
– Energy storage
– Cell membranes
– Steroid hormones
– other
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Proteins
• Large molecules—Long folded chains
• Made up of many different combinations of 20
different types of amino acids
• Differences in # & arrangement of amino acids
causes proteins to bend into different shapes.
• The shape of the protein determines the
Function of proteins
proteins function
1.
2.
3.
4.
5.
Defense ex antibodies
Structure ex muscle
Enzymes ex amylase
Transport ex hemoglobin
etc
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Nucleic Acids
• Long chains of molecules called nucleotides
• 2 types
– DNA (deoxyribonucleic acid)
• Stores hereditary information
– RNA (ribonucleic acid)
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Viruses are exceptions to the cell theory, but they
have some characteristics of living things. What is
one of these characteristics?
1.
2.
3.
4.
They are made up of many specialized cells.
They contain genetic material.
They reproduce by mitosis.
They contain chlorophyll.
Correct Answer Number: 2
Explanation: Although virus' contain genetic material,
they can not reproduce without being inside of a
host cell. Many scientists question if they can be
considered living or not, as this is the only life
function they are capable of performing.
Which formula represents an organic compound?
1.
2.
3.
4.
Mg(OH)2
NaCl
C12H22O11
NH3
Correct Answer Number: 3
Explanation: Organic compounds have Carbon (C)
and Hydrogen (H) and are part of, or produced
by, or excreted by living organisms.
Which is an organic compound found in most cells?
1.
2.
3.
4.
glucose
water
sodium chloride
oxygen gas
Correct Answer Number: 1
Explanation: Organic means that the molecule
contains carbon bonded to hydrogen. Only
glucose, whose molecular formula is C6H12O6,
has this. Although most cells also have an
abundant amount of water (H2O) it is inorganic,
as is sodium chloride (NaCl) and oxygen gas (O2).
Which are the four most abundant elements in
living cells?
1.
2.
3.
4.
carbon, oxygen, nitrogen, sulfur
carbon, oxygen, hydrogen, nitrogen
carbon, oxygen, sulfur, phosphorus
carbon, sulfur, hydrogen, magnesium
Correct Answer Number: 2
Explanation: Although all of these elements are
found in living cells, the most abundant are
carbon, hydrogen and oxygen (for carbohydrates
and lipids) and nitrogen (for proteins and nucleic
acids).
Which pair of compounds can be classified as
inorganic?
1.
2.
3.
4.
nucleic acids and minerals
proteins and water
water and salts
nucleic acids and proteins
Correct Answer Number: 3
Explanation: Organic compounds contain carbon
and hydrogen bonds. Both nucleic acids and
proteins contain these. Water (H2O) and salts (ex:
NaCl) do not.
Nucleotides
Units that make up DNA molecule
Made of three parts
1. 5 carbon sugar (deoxyribose)
2. Phosphate group
3. Nitrogen bases
4 kinds of nitrogen bases
1.
2.
3.
4.
Adenine
Guanine
Cytosine
Thymine
(A)
(G)
(C)
(T)
Chargaff’s Rule
• A=T and G=C
X-Ray Evidence
• Rosalind Franklin
• British Scientist
• Used a technique called
X-Ray diffraction
• Provided important
clues about the
structure of DNA
Watson & Crick
Prokaryotic Cells
• Prokaryotic cells have a single circular
DNA molecule that contains nearly all of
its genetic information
• Located in the cytoplasm
Eukaryotic Cells
• Much more complex
• 1000 times the amount of DNA as
prokaryotes
• DNA is located in the nucleus in the
form of chromosomes
DNA coils around histones to form nucleosomes,
which coil to form chromatin fibers. The chromatin
fibers super coil to form chromosomes that are visible
in the metaphase stage of mitosis.
Semiconservative Replication
• Parental strands of DNA separate, serve as
templates, and produce DNA molecules that
have one strand of parental DNA and one
strand of new DNA.
Types of RNA
1. Messanger RNA (mRNA)
• Serve as messangers from DNA to the
rest of the cell
2. Ribosomal RNA (rRNA)
• Type of RNA that makes up parts of
ribosomes
3. Transfer RNA (tRNA)
• Transfers each amino acid to the
ribosome as it is specified by the mRNA
Transcription
• RNA molecules are produced by copying part
of the DNA sequence into RNA
• Transcription requires an enzyme known as
RNA polymerase
• During transcription, RNA polymerase binds to
DNA and separates the DNA strands. RNA
polymerase then uses one strand of DNA as a
template from which nucleotides are
assembled into a strand of RNA.