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Nucleic acids:

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Nucleic acids: Information molecules Contain H, O, N, C, and P Monomers: Nucleotides Nucleotide has three parts 5 carbon sugar Nucleic acid/nitrogenous base – PowerPoint PPT presentation

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Title: Nucleic acids:


1
Nucleic acids
  • Information molecules
  • Contain H, O, N, C, and P
  • Monomers Nucleotides
  • Nucleotide has three parts
  • 5 carbon sugar
  • Nucleic acid/nitrogenous base
  • phosphate group

2
Nucleic Acids
  • Function
  • genetic material
  • stores information
  • genes
  • blueprint for new cells
  • blueprint for next generation
  • transfers information
  • blueprint for building proteins
  • DNA ? RNA ? protein

3
Nucleic Acids
  • Examples
  • DNA
  • Deoxyribonucleic Acid
  • RNA
  • Ribonucleic Acid

4
Nucleic acids
nucleotides
  • Building block

nucleotide nucleotide nucleotide nucleotide
  • 5 different nucleotides
  • different nitrogen bases
  • A, T, C, G, U

Nitrogen basesIm the A,T,C,G or Upart!
5
Nucleotide chains
  • Nucleic acids
  • nucleotides chained into a polymer
  • DNA
  • double-sided
  • double helix
  • A, C, G, T
  • RNA
  • single-sided
  • A, C, G, U

strong bonds
6
DNA
  • Double strand twists into a double helix
  • weak bonds between nitrogen bases join the 2
    strands
  • A pairs with T
  • A T
  • C pairs with G
  • C G
  • the two strands can separate when our cells
    need to make copies of it

7
Proteins
  • Highly diverse group
  • Elements C, H, N, and O

8
Proteins
  • Function
  • many, many functions
  • Structure Movement
  • muscle
  • Regulated chemical reactions and processes
    enzymes
  • help chemical reactions
  • Transport substances in and out of cells
  • part of cell membranes
  • Pigments
  • skin color, melanin
  • Hormones
  • signals from one body system to another
  • Insulin
  • Immune system
  • protect against germs

9
Proteins
  • Examples
  • muscle
  • skin, hair, fingernails, claws
  • collagen, keratin
  • pepsin
  • digestive enzyme in stomach
  • insulin
  • hormone that controls blood sugar levels

10
Proteins
  • Building block
  • In a condensation reaction, two amino acids form
    a covalent bond, called a peptide bond.
  • Two amino acids bond to form a dipeptide.
  • A very long chain of amino acids is called a
    polypeptide.

amino acids
11
Amino acid chains
  • Proteins
  • amino acids chained into a polymer
  • Each amino acid is different
  • Some hydrophilic, some hydrophobic
  • Some positively charged, some negative, some
    neutral
  • Some polar, some nonpolar

12
Water-fearing amino acids
  • Hydrophobic
  • water fearing amino acids
  • try to get away from water in cell
  • the protein folds

13
Water-loving amino acids
  • Hydrophilic
  • water loving amino acids
  • try to stay in water in cell
  • the protein folds

14
Its shape that matters!
  • Proteins fold twist into 3-D shape
  • Different shapes different jobs
  • Proteins do their jobs, because of their shape
  • Unfolding a protein destroys its shape
  • wrong shape cant do its job
  • unfolding proteins denature
  • temperature
  • pH (acidity)

unfoldeddenatured
folded
15
Enzymes are proteins
  • Each enzyme is the specific helper to a specific
    reaction
  • each enzyme needs to be the right shape for the
    job
  • enzymes are named for the reaction they help
  • sucrase breaks down sucrose
  • proteases breakdown proteins
  • lipases breakdown lipids
  • DNA polymerase builds DNA

16
Nothing works without enzymes!
  • How important are enzymes?
  • all chemical reactions in living organisms
    require enzymes to work
  • building molecules
  • synthesis enzymes
  • breaking down molecules
  • digestive enzymes
  • enzymes speed up reactions
  • catalysts

17
Enzymes arent used up
  • Enzymes are not changed by the reaction
  • used only temporarily
  • re-used again for the same reaction with other
    molecules
  • very little enzyme needed to help in many
    reactions

substrate
product
enzyme
18
Its shape that matters!
  • Lock Key model
  • shape of protein allows enzyme substrate to fit
  • specific enzyme for each specific reaction

19
Enzyme Action
Product is released. Enzyme is available again.
Reactants bind to the enzyme at the active site.
Chemical reaction changes reactants to
products.
20
Enzyme vocabulary
  • Enzyme helper molecule
  • Substrate molecule that enzymes work on
  • Enzyme-substrate complex enzyme molecule
    temporarily joined
  • Active site part of enzyme that substrate
    molecule fits into

21
What affects enzyme action
  • Correct protein structure
  • correct order of amino acids
  • why? enzyme has to be right shape
  • Temperature
  • why? enzyme has to be right shape
  • pH (acids bases)
  • why? enzyme has to be right shape

22
Enzyme concentration
  • Effect on rates of enzyme activity
  • as increase amount of enzyme increases how fast
    the reaction happens, up to a point
  • more enzymes more frequently they collide with
    substrate

23
Substrate concentration
  • Effect on rates of enzyme activity
  • as increase amount of substrate increases how
    fast the reaction happens, up to a point
  • more substrate more frequently they collide
    with enzyme

24
Temperature
  • Effect on rates of enzyme activity
  • Optimum temperature
  • greatest number of collisions between enzyme
    substrate
  • human enzymes
  • 35- 40C (body temp 37C)
  • Raise temperature
  • denature protein unfold lose shape
  • Lower temperature T
  • molecules move slower
  • decrease collisions

25
pH
  • Effect on rates of enzyme activity
  • pH changes protein shape
  • most human enzymes pH 6-8
  • depends on where in body
  • pepsin (stomach) pH 3
  • trypsin (small intestines) pH 8

26
Effects of Altered pH or Temperature on Enzyme
Action
Chemical reaction cant occur. Reactants dont
get changed to products.
A change in the enzyme prevents reactants from
binding. Shapes dont match.
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