Biochemistry and Cell Structure
2-3 Carbon Compounds
The Chemistry of Carbon
 Organic Chemistry – the study of all compounds that contain carbon atoms
 All organic compounds contain Carbon
 3 Ways Carbon Atoms Bond
1. Straight Chain
2. Branched Chain
3. Rings
Organic Compounds
 4 Types of Organic Compounds Essential to Living Things.
1. Carbohydrates
 composed of C, H, O
 1:2:1 ratio of C:H:O
 Body breaks down sugars to use as energy for cell activity
 3 Types of Carbohydrates
A. Monosaccharide
 Simple sugars
 Made up of one sugar molecule
 Ex. Glucose, fructose, galactose
B. Disaccharide
 Double sugar – two monosaccharide molecules linked together
 Ex. Sucrose (table sugar)
C. Polysaccharide
 The largest and composed of many monosaccharide molecules
 Ex. Glycogen (in humans)
Cellulose & starch (used as food storage by plants)
2. Lipids
 Fatty acids
 Large proportion of C, H compared to O
 Lipids are used for:
 energy storage
 insulation
 protective coatings
 key component of cell membrane
 Common categories of lipids are
A. Triglycerides
 Fats – solid at room temperature
 Oils – liquid at room temperature
B. Wax
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 Used for protection by your ear to keep gunk out
 Used by plants as waterproofing protection
C. Steroids
 These are considered lipids because they can’t combine with water.
3. Nucleic Acid
 A complex molecule that stores cellular information in the form of a code
 Nucleotides – make up nucleic acid
 Nucleic acids store and transmit hereditary, or genetic information
 Two Kinds of Nucleic Acids
 RNA – ribonucleic acid
 Contains sugar ribose
 DNA – deoxyribonucleic acid
 Contains sugar deoxyribose
4. Proteins
 Made up of C, H, O, N
 Essential to life
 Provide structure for tissues and organs
 Carry out cell metabolism
 Amino Acids – basic building blocks of proteins
 Proteins are Important in…
 Contracting muscle tissue
 Transporting oxygen in blood
 Providing immunity,
 Carry out chemical reactions
 Digestion of food
2-4 Chemical Reactions and Enzymes
Chemical Reactions
 Chemical Reaction – a process that changes one set of chemicals into another set
of chemicals
 Reactants – elements or compounds that enter a chemical reaction
 Products – elements or compounds produced by a chemical reaction
 Activation Energy – the energy that is needed to get a reaction started
Enzymes
 Type of catalyst
 Protein that speeds up a chemical reaction
 Lowers the amount of activation energy needed
 Lowering the activation energy effects how fast the reaction is completed.
The Induced Fit Model
 Enzymes are specific to what substrate they will react with
 The substrate fits into the enzyme like a lock and a key
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 The active site on the enzyme and the shape of the substrate are not a perfect
match
 When they fit together they “mold” to each other
 Once the reaction is over, the substrate is released
 The enzyme returns to the original shape and reacts with another substrate
Regulation of Enzyme Activity
 What can affect how enzymes work?
 pH
 if pH is to acidic or basic the enzyme will not work
 most enzymes work best at 7 (neutral)
 Temperature
 If it is to hot or cold the enzyme will not work
 Denature – enzymes active site changes shape and will not bind to the substrate, so
no reaction
 Enzymes play essential roles in
 Regulating chemical reactions
 Make materials that cells need
 Releasing energy
 Transferring information
7-1 Life Is Cellular
The Discovery of Cells
 Cells are the basic units of life
 Your body is made of 75 – 100 trillion cells
 Robert Hooke – 1665
 Used one of the first microscopes to view a slice of cork
 He saw that cork is made up of lots of little boxes
 He named them cells
 Anton van Leeuwenhoek – 1675
 Used a microscope to view a drop of pond water
 He saw “critters” living in the water
 Schleiden
 Said that all plants are made entirely of cells
 Schwann
 Said that all animals are made up entirely of cells
 Virchow
 Said that all cells come from existing cells
The Cell Theory
 There are 3 parts to the Cell Theory
1. All living things are made of cells
2. Cells are the basic units of structure and function
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3. Cells are produced from existing cells
2 Types of Cells
1. Prokaryotes
 Pro means before
 Karyote means nucleus
 A cell that does not contain a nucleus
 DNA is free floating inside the cell
 Do not have membrane bound organelles
 Most are single-celled organisms (unicellular)
 First appeared about 2 billion years ago
 Ex. Bacteria
2. Eukaryote
 Eu means true
 A cell that contains a nucleus with DNA inside
 They have organelles
 Are either single celled or made of many cells (multicellular)
 Evolved 1.5 billion years ago
 Ex. Plants, animals, fungi, protists
7-2 Eukaryotic Cell Structure
 Two different types of Eukaryotic Cells
 Plant Cell
 Animal Cell
 Organelles – membrane bound structures in a eukaryotic cell that manages the cell’s
functions
Cell Shape
 Cytoplasm
 The clear gelatinous fluid inside a cell
 Surrounds all of the organelles
 Cell Membrane
 Thin, flexible barrier around a cell
 Regulates what enters and leaves the cell
 Cell Wall
 A rigid structure located outside the plasma membrane that provides additional
support and protection
 Occurs in plant cells, fungi, most bacteria and some protists.
Protein Production
 Nucleus
 cells largest organelle
 Is surrounded by a double membrane called the nuclear envelope
 Contains DNA – directions to make proteins
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 Nucleolus
 Organelle within the nucleus
 Makes ribosomes
 Ribosomes
 Ribosomes move out of nucleus
 Where proteins are made
Assembly, Transport and Storage
 Endoplasmic Reticulum (ER)
 Site of cellular chemical reactions
 A series of folded membranes
 Transports proteins and other materials to the golgi apparatus
 Two types of ER
1. Rough ER
 Covered with ribosomes
 Makes proteins
2. Smooth ER
 Contains no ribosomes
 Makes lipids
 Golgi apparatus
 “Packaging and distribution” center of cell
 Sorts proteins into packages (vesicles) to be sent to the appropriate destination
in the cell or outside of the cell
 Vacuoles
 Temporary storage of materials like food, enzymes and other materials needed
by the cell and cell waste
 In plant cells there is one very large vacuole
 In animal cells there are many small vacuoles
 Lysosomes
 Small organelles filled with enzymes
 Enzymes break down lipids, carbohydrates, worn out organelles, viruses and
bacteria.
 “recycling centers”
 Plastids
 Only in plants
 Some are used to store starches, lipids and others contain pigments to give them
color
Energy Transformers
 Mitochondria
 Powerhouse of the cell
 make energy for the cell
 Chloroplasts
 Type of plastid
 Only in green plants and some protists
 Capture light energy and produce food
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 Necessary for photosynthesis
 Contain Chlorophyll - green pigment
Structures for Support and Locomotion
 Cytoskeleton
 Give cells support structure
 Composed of tiny rods called microtubules and filaments called microfilaments
 Centrioles
 Microtubules that help with cell division
 Cilia
 Short numerous hairlike projections
 Move in a wavelike motion to help cell move
 Flagella
 Long tail like projection
 Move with a whiplike motion
Difference between Plant and Animal Cells
Plant Cell
Animal Cell
 photosynthesis
no photosynthesis
 Contain chloroplasts
no chloroplasts
 Contain chlorophyll
no chlorophyll
 Cell wall
no cell wall
 One large vacuole
many small vacuoles
 Square
round
 In general larger
smaller
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