Biochemistry Flashcards
Importance of carbohydrates
- Short term energy (glucose to ATP)
- Energy storage (glycogen in liver/muscles, starch in plants)
- Receptors and identification tags (cell membrane markers)
- Structural material (plant walls: cellulose, insect exoskeleton: carbohydrate chitin)
Protein functions
- Provide structural support (elastin in cartilage, and in bone/muscle cells)
- Movement (actin and myosin in muscle cells)
- Metabolic functions
- enzymes (biochemical catalysts)
- antibodies (immune system fight disease)
- transport (in cell membrane act as channels)
- hormones (control many aspects of homeostasis)
Nucleotides
Consists of: - 5 carbon sugar - phosphate group - nitrogenous base (1 or 2 rings) In DNA: - A to T - C to G In RNA: - A to U - C to G
DNA: Deoxyribonucleic acid
- Composed of monomers (nucleotides)
- Makes up chromosomes and genes
- Controls all cell activities (cell division & protein synthesis)
- undergoes mutations important to the process of evolution
Amino Acids
Functional groups 1. Amine (-NH) 2. Carboxyl (-COOH) 3. R (remainder) • Composes proteins • Each has different R group * know how to draw* • There is 20 essential - make 12 - eat 8
ATP: Adenosine Triphosphate
• Type of nucleotide
• Used as primary source of energy in cells
Consists of
- sugar ribose, base adenine, and 3 phosphate groups attached to ribose
• produced in mitochondria during cellular respiration
Base Pair Names
A: adenine
T: thymine
C: cytosine
G: guanine
Peptide bonds
• Bond between 2 amino acids
• formed through dehydration synthesis
know how to draw
Biochemical reaction types
- Dehydration synthesis: forms polymers and produces water
2. Hydrolysis: water breaks up molecule
Polysaccharides
• Contains large number of monosaccharides
• 3 most important types made of carbohydrates
- starch
- glycogen
- cellulose
Disaccharides
• sugar formed when two monosaccharides join by glycosidic linkage
G= glucose
G + G ——> G-G + H2O
Glucose
• Makes ATP
• Bonds to form glycogen
• is a carbohydrate
know how to draw
Monosaccharides
- Simple sugars with one unit molecule
* most common is glucose
Polar molecule
• Molecule with uneven distribution of charge
- each molecule has positive and negative end
- know how to draw H2O molecule*
- angle is 104.5
- H pos. O neg.
Hydrogen bonds
• Water molecules attract each other H+ attracts O-
• Weak bond/easily broken
* know how to draw*
Water facts
- Most abundant substance on surface of the planet
- Absolutely essential to all life
- Universal solvent (does not dissolve ALL)
RNA: Ribonucleic Acid
- Composed of monomers (nucleotides)
- Works with DNA to direct protein synthesis
- Linear/Single strand
Characteristics of living things
- Have orderly structure (made of one or more living cells)
- Reproduce (have DNA/RNA that hold info and control life’s processes)
- Grow and develop (use energy for growth and maintenance
- Respond to environmental stimuli
Why organisms require water
- Only substances dissolved in water can enter cell membrane (glucose, amino acids via passive diffusion)
- Water carries away dissolved wastes from cells and excretes in liquid (urine and sweat)
- Water and water based solutions acts as lubricant (joints lubricated by fluid called synovial fluid)
- Water regulates temperature
- Important for hydrolysis reactions
Lipids and their importance
Fats, oils, and waxes
- Long term energy storage
- Insulation “blubber” maintain body temperature
- Padding of vital organs
- Structural (cell membranes are mostly composed of phospholipids)
- Chemical messengers (steroid hormones ex. Testosterone, estrogen…)
Types of fats
- Saturated fatty acids: no double bond between carbons, solid at room temp. “Saturated with hydrogen’s”
- Unsaturated fatty acids: at least one double bond, tends to be liquid at room temp.
- Neutral fats (triglycerides): formed by dehydration synthesis between glycerol and 3 fatty acids
- Phospholipids: same as neutral fats, but on phosphate group and 2 fatty acids
The cell theory
- Cells are the basic units of life
- All organisms are made up of one or more cells
- All cells arise from preexisting cells
Divisions of cells
Prokaryotes: cells that do not contain nucleus or membrane bound organelles
Eukaryotes: cells that do contain a nucleus and membrane bound organelles
Plant vs animal cells
- Plant cells contain cell wall
- Plant cells have plastids (chloroplast)
- Plant cells contain a central vacuole that holds mostly water. Animal cells have small ones holding food and water
Cell membrane structure
• selectively permeable
- some substances can cross without aid, but not all
• phospholipid bilayer
- phosphate heads are polar and hydrophilic, interact with water environments/outsides
- fatty acid tails are non polar and hydrophobic, are on inside
• cholesterol
- found in membrane: prevent fatty acid tails from sticking together
Cell membrane functions
- transport of materials in and out of cells
- cell recognition
- maintaining cell integrity
- homeostasis
The fluid mosaic model
- cell membrane both liquid and solid properties
- “fluid sea” is phospholipid bilayer (lipids and carbohydrates are boats)
- “mosaic” is solid embedded proteins in bilayer
Proteins in fluid mosaic model
- receptor proteins: proteins wit receptor so certain molecules can attach to surface
- protein channels: provide mechanisms for lipid insoluble molecules to cross the membrane
- channels with ATP: some substances bond to proteins and are propelled through membrane with expenditure of energy
Nucleus (controls all cell function)
- surrounded by phospholipid bilayer (nuclear envelope) which has pores to control molecules moving in and out
- contains DNA and is site of mRNA production
- chromosomes function in packaging of DNA during nuclear division
- contains 1+ nucleolus which is site of rRNA synthesis
Endoplasmic reticulum
• series of membranous canal through which molecules can be transported
- Rough ER: ribosomes attach to, site of protein synthesis
- Smooth ER: site of lipid synthesis, detoxifies drug and chemicals in the cell
Ribosomes-rRNA
- one of smallest yet most abundant organelle
- made up of two rRNA subunits and joined proteins
- assembly is in cytoplasm
- carries out protein synthesis
Golgi apparatus
- often continuous with ER
- each sac contains enzymes that modify proteins that pass through
- function is to modify, assemble, package, store, and secrets substances
Vacuoles and vesicles
• used for transport Formation: 1. Pinching off from Golgi apparatus 2. Endocytosis of the cell membrane 3. Extensions of the ER membrane
Lysosomes
Sacks of digestive enzymes
- Cellular digestion: destroy bacteria
- Auto digestion: disposal of damaged cell components
- Break down if whole cell: suicide sac
Mitochondria
“Powerhouse” • large double membraned structure - outer membrane surrounds mitochondria - inner membrane is convoluted with folds called cristae • cellular respiration occurs here
Cellular respiration reaction
• combustion
Glucose+O2——> H2O+energy(ATP)
Plastids
Food makers of the world
• found in plants
• most common is chloroplast
• chloroplasts contain chlorophyll which is used for photosynthesis
Photosynthesis reaction
Sunlight+CO2+H2O—> glucose+O2(energy)
Cytoplasm
- Cytosol: jelly like substance where reactions take place
2. Organelles: each has specific function
Cytoskeleton
• network of micro tubes - made of protein and microfilaments • maintains shape • anchors organelles • help the organelles move as necessary
Cilia and flagella
- function in cell movement
- cilia are shorter and move in rowing motion
- flagella are longer and move in whip like fashion
Centrioles
Animal cells only
• help organize the cell during cell division
Cell wall
Plant cell only
• non living layer surrounding outer cell membrane
• composed of cellulose
• semi permeable membrane that supports and protects plant cells
General types of transport
- Passive transport (no energy)
- diffusion
- osmosis
- facilitated transport - Active transport (requires energy)
- active transport
- endocytosis
- exocytosis
Diffusion
- molecules move from and area of high concentration to low
- only certain molecules can diffuse through membrane: lipid soluble molecules, (steroids, alcohols, and other lipids) gases (CO2 and O2), water through charges protein pores (aquaporin)
Ways to increase rate of diffusion
- Increase temperature
- Increase concentration gradient
- Decrease molecule size
Osmosis
The diffusion of water
Solute
Particles dissolved in water
Solvent
Liquid which dissolved solute (usually water)
Solution
Combination of solute and solvent
Types of solutions
- Hypotonic: less solute molecules than inside cell
- Hypertonic: more solute molecules than inside cell
- Isotonic: same number of solute molecules as inside cell
Osmotic pressure
• pressure due to flow of water from are of greater concentration of solvent to that of lesser concentration solvent
• greater concentration differences across membrane= greater osmotic pressure
* water uses protein to pass through membrane
Facilitated transport
- uses protein carrier
- highly specific: each carrier moves only one type of molecule
- no energy required
- can move things like glucose and amino acids
Active transport
- uses protein carrier
- requires ATP
- moves substance from high concentration to low
Endocytosis and exocytosis
• require ATP
• endocytosis: cell membrane forms vesicle around a substance to be taken into cell
- phagocytosis: “cell eating” larger molecule
- pinocytosis: “cell drinking” smaller molecules
• exocytosis: reverse of endocytosis. Vesicle fuses with cell membrane releasing contents
