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What model do enzymes work by?
"lock and Key model"
water makes up approx what percent of:
1) human body
2) human blood
- 50-60% of human body
- 92% of human blood
the abilility of one substance to disolve in another
Define Induced Fit Hypothesis:
enzymes change shape to accommodate the shape of specific reactants
any substance containing free ions
do not have a uniform composition throughout themixture and can be separated physically
same composition throughout with uniform appearance
a proton donor or any substance that releases hydrogen ions
a proton acceptor or any substance that binds to oraccepts hydrogen ions
a compound consisting of a cation other than a hydrogen ion and an anionother than a hydroxide ion. Example: NaCl
- an ionic compound that resists changes in its pH
- When H+ added, buffer removes it
- When H+ removed, buffer replaces it
required in the final step in theseries of reactions used to extract energy from food.
Carbon dioxide (CO2):
- produced during the catabolism of organic compounds.
- Metabolic waste product.
- Combines with water in plasma and
- forms H+ thus affecting acid/base balance
generally, substances that do not contain carbon
Water, oxygen, calcium phosphate, metalionsExceptions: CO, CO2, and HCO3-
study of carbon-containing substances
- composed of carbon, hydrogen, oxygen.
- Divided into monosaccharides, disaccharides, polysaccharides
- Energy sources and structure
- composed mostly of carbon, hydrogen,oxygen.
- Relatively insoluble in water.
- Functions: protection, insulation,component of cell membranes, energy source
- composed of carbon, hydrogen, oxygen, nitrogen, sometimes iodine.
- Functions: regulate processes, aid
- transport, protection, muscle contraction, structure, energy
- composed of carbon, hydrogen, oxygen, nitrogen, phosphorus.
- Examples: DNA, RNA, ATP(nucleotide)
The building blocks of carbohydrates are?
- Two simple sugars bound together by
- dehydration synthesis
- Examples: sucrose, lactose, maltose
- Long chains of many monosaccharides.
- Glycogen formed by animals.
- Starch and cellulose formed by plants
- Starch in food is used as a
- source of monosaccharides
- Cellulose in food acts as fiber
- (bulk) in the diet
- Ingested and broken down by hydrolysis
- Triglycerides: composed of glycerol and three
- fatty acids.
- Functions: protection, insulation, energy
Saturated fats –
contains all single bonds inthe carbon chain, which produces a more rigid structure. Solid at room temperature
- contains one (mono) or more(poly) double bonds in the carbon chain, which produces a more relaxedstructure. Liquid at room temperature.
- Better because they do not stickto the inside of blood vessels.
Trans fats –
- unsaturated fats that are artificially altered to be more saturated.
- Are the highest CV risk fat
- Polar (hydrophilic) at one end; nonpolar
- (hydrophobic) at the other.
- For example, water is a polar
- molecule and oil is a non-polar molecule. A polar and non-polar combination
- will not form a solution; therefore, oil and water won't form a solution.
- Function: important structural component of cell
- Cholesterol, bile salts, estrogen,
- Carbon atoms arranged in four
- Functions: physiological regulators and
- component of cell membranes
true or false
Cholesterol cannot dissolve in the blood. It has to be transported to and from the cells by
carriers called lipoproteins
lipoprotein, or LDL
- is known as “bad”
- Composed mainly of cholesterol and have
- very little protein.
- Primarily responsible for depositing
- cholesterol within arteries.
- High levels of LDLs are associated with
- an increased risk for coronary heart disease.
High-density lipoprotein =
HDL, is known as “good” cholesterol. Composed mainly of proteins, with onlysmall amounts of cholesterol.Help remove cholesterol from artery wallsand transport it to the liver for elimination from the body. Higher HDL levels actually protectagainst coronary heart disease
what is the building blocks of protein?
covalent bonds formed between aminoacids during protein synthesis
a molecule consisting of two amino acids joined by a single peptide bond.
A peptide consisting of 2 or more aminoacids
why are essential amino acids essential?
- because the body does not synthesize them, making it essential to include them in one's diet in order to
- obtain them.
Nonessential amino acids
The amino acids that your body can produce on its own.
- Proteins with the primary purpose of producing the essential structural components of the cell.
- Provide stiffness and rigidity to otherwise-fluid biological components
- Have the ability to carry out metabolic processes.
- Example: enzymes
what is the building blocks of DNA and RNA
- Composed of a five-carbon sugar, a nitrogenous base, and a phosphate
- Include the nucleic acids (DNAand RNA) and ATP
what does DNA stand for
In humans, DNA is located primarily inside...
the cell nucleus, but some DNA is also located in mitochondria
The main role of DNA is?
the long-term storage of information
what are the 4 nitrogenous bases of DNA and which bond with which?
Adenine (A) binds with thymine (T), Cystosine (C) binds with guanine (G)
what does RNA stand for
RNA: Ribonucleic acid
in stead of thymine RNA has what as its 4th nitrogenous base
- Energy currency of the body
- Provides energy for other chemical reactions such as anabolism or drive cell processes such as muscle contraction
- All energy-requiring chemical reactions stop when there is inadequate ATP
Basic Structure of the Cell (3)
- Plasma membrane
- Cytoplasm containing organelles
what are the Functions of the Cell
- Cell metabolism and energy use
- Synthesis of molecules
- Communication. Cells produce and receive electrical
- and chemical signals
- Reproduction and Inheritance. Each cell contains DNA. Some cells are
- specialized to gametes for exchange during sexual intercourse
- Separation of intracellular vs. extracellular materials
- Production of charge difference (membrane potential) across the membrane by regulation of intracellular and extracellular ion concentrations
- Outside of membrane positively charged compared to inside because of gathering ions along outside and inside
- Phospholipids and cholesterol predominate
- Phospholipids: bilayer. Polar heads facing water in the interior and exterior of the cell (hydrophilic); nonpolar tails facing each other on the interior of the membrane (hydrophobic)
- Cholesterol: interspersed among phospholipids. Amount determines fluid nature of the membrane
- Fluid nature provides/allows Distribution of molecules within the membrane
- Phospholipids automatically reassembled if membrane is damaged
- Membranes can fuse with each other
Glycoproteins and Glycolipids
- Allow cells to identify one another or other molecules
- Recognition of oocyte by sperm cell
- Intercellular communication
2 types of Channel Proteins
gated and non-gated
non gated ion channel
- always open
- Responsible for the permeability of the plasma membrane to ions when the plasma membrane is at rest
Gated ion channels
can be opened or closed by certain stimuli
Ligand gated ion channel:
open in response to small molecules that bind to proteins or glycoproteins
Voltage-gated ion channel:
open when there is a change in electrical charge across the plasma membrane
- Also called transporters
- Integral proteins move ions from one side of membrane to the other
- Have specific binding sites
- Protein changes shape to transport ions or molecules
- Resumes original shape after transport
what are the three forms of carrier proteins?
- Uniporters – moves one particle
- Symporters – move two particles in the same direction at the same time
- Antiporters – move two particles in opposite directions at the same time
- Proteins or glycoproteins in membranes with an exposed receptor site
- Can attach to specific chemical signal molecules and act as an intercellular communication system
- Ligand can attach only to cells with that specific receptor
Receptors Linked to Channel Proteins
- Receptor molecules linked to channel proteins
- Attachment of receptor-specific chemical signals (e.g., acetylcholine) to receptors causes change in shape of channel protein, Channel opens or closes
- Changes permeability of cell to some substances
- some act to catalyze reactions at outer/inner surface of plasma membrane.
- Surface cells of small intestine produce enzymes that digest dipeptides
5 types of Movement through the Plasma Membrane
- Mediated Transport
- Facilitated diffusion
- Active transport
- Movement of solutes from an area of higher concentration to lower concentration in solution
- Concentration gradient: difference between two points
- Diffusion of water (solvent) across a selectively permeable membrane.
- Water moves from an area of low concentration of solute to an area of high concentration of solute
solutions with the same concentrations of solute particles
Solution with a greater concentration of solute is
Solution with a lesser concentration of solute is
shrinkage or swelling - isotonic?
cell neither shrinks nor swells
shrinkage or swelling - hypotonic
cell swells (lysis)
shrinkage or swelling - hypertonic
cell shrinks (crenation)
- Involve carrier proteins or channels in
- the cell membrane
- Specificity for a single type of molecule
- Competition among molecules of similar shape
- Saturation: rate of transport limited to number of available carrier proteins
Mediated Transport – Facilitated Diffusion
- Facilitated diffusion: carrier- or channel-mediated. Passive.
- Move large, water soluble molecules or electrically charged molecules across the plasma membrane.
- Amino acids and glucose in, manufactured proteins out.
Mediated Transport – Active Transport
- ATP-Powered Transport
- Requires ATP. The use of energy allows the cell to accumulate substances
- Rate of transport depends on concentration of substrate and on concentration of ATP
- Example: Na+/K+ exchange pump that create electrical potentials across membranes
- Internalization of substances by formation of a vesicle
- Active transport
- Phagocytosis (shown): “cellular eating”
- Pinocytosis: “cellular drinking”
- Receptor-mediated endocytosis
- Accumulated vesicle secretions expelled from cell
- Active transport
- Secretion of digestive enzymes by
- Secretion of mucous by salivary
- Secretion of milk by mammary