Lab 1 Flashcards
In homeostatic control (thermostat in a room), the event or factor being controlled is the
variable, X (room temperature)
variable, X (room temperature) is maintained within a narrow limit around a
set point (level or range, the temperature at which you have set the thermostat)
A ? analyzes the information received from ? and determines a response, which is carried out by ?
- control or integrating center (the thermostat)
- sensors (temperature sensors)
- effectors (furnace or air conditioner)
In the body, information travels from a ? along ? to the ?. This integrates input from other receptors with the ? and adjusts the output of the ? via an ?.
- sensor or receptor
- an afferent pathway
- control center (usually the hypothalamus or midbrain)
- set point
- effector
- efferent pathway
occurs when a change in a variable triggers a response which adjusts in the opposite direction of the initial change
negative feedback
fluctuations constantly occur above or below a set point
dynamic constancy
the average value of the range of the variable
set point
The ? of the negative feedback mechanism can be observed by measuring how much deviation from the set point occurs before a compensating response is activated. Control can be further refined by the addition of ? which have the opposite effect on the variable. Even more efficient control utilizes ?. They are usually antagonistic to each other.
- sensitivity
- antagonistic effectors
- two sensors and two effectors
the response of the effectors to any change in the variable causes an amplification of the changes. In other words, a change causes the effectors to respond in the same direction as the change.
Positive Feedback
When a person undergoes strenuous exercise or is exposed to high environmental temperatures, the body’s homeostatic mechanisms go to work. Under heat stress,? in the skin send messages through the ? to the?. This sends messages via the ? to the ? and ?.
- thermoreceptors
- afferent sensory pathways
- posterior hypothalamus (integrating center)
- efferent autonomic pathways
- sweat glands
- smooth muscles in arterioles (effectors).
occurs when strenuous exercise or high environmental temperatures cause the body’s homeostatic mechanisms to be overtaxed
Heat exhaustion
can follow heat exhaustion if the regulatory center in the hypothalamus fails due to continued high body temperature
Heat stroke
With a drop in body temperature, the ? cause a different response. The ? are constricted in the skin via the ? and sweat production is either decreased or stopped to prevent evaporative heat loss. Other behavioral responses may be used (e.g. adding more clothing, curling up) to keep core body temperature up. Collectively, these responses are referred to as ?. The ? utilizes skeletal muscles to increase body temperature by shivering.
- thermoreceptors, afferent pathways, hypothalamus, and efferent pathways
- arterioles
- sympathetic nervous system
- nonshivering thermogenesis
- efferent somatic nervous system
The ? and glucagon have an opposite effect on maintaining blood glucose levels.
antagonistic effectors insulin,
When blood glucose levels rise (after a meal) ? is released from the beta cells of the pancreatic islets.
insulin
? is released from pancreatic alpha cells in response to low blood sugar.
Glucagon
Glucagon also induces the liver (and some other cells such as muscle) to make glucose out of building blocks obtained from other nutrients found in the body (e.g. protein). This is termed ?.
gluconeogenesis
The four classes of organic molecules
carbohydrates, proteins, lipids, and nucleic acids
Each class of organic molecules is composed of a small organic subunit called a ?, which can combine to form a ?.
monomer, polymer
? involves the removal of a water molecule as monomers are bound together. ? reactions
divide polymers by breaking the chemical bonds between the monomers with the addition of a water
molecule.
Condensation synthesis, Hydrolysis
simple sugar monomers found in carbohydrates
Monosaccharides
two sugars linked together
Disaccharides
long chains of glucose molecules, forming a polymer
Polysaccharides
straight chain of glucose with very few branches found in plants
polysaccharide starch
highly branched chain of glucose found in animals (used as energy storage)
Glycogen
the primary constituent of plant cell walls, which is indigestible by humans. We refer to this material as fiber.
Cellulose
a varied group of organic molecules that provide insulation and energy storage as fats, as well as act as chemical messengers in the form of steroids
Lipids
The monomer of a lipid is the ?. It is a long chain of carbon and hydrogen with a carboxyl group at one end.
fatty acid
have no double bonds in the chain, which means they have a maximum number of hydrogen (found in animal fats)
Saturated fatty acids
? have double bonds in the carbon chain, which means less hydrogen (found in plant oils).
Unsaturated fatty acids
The polymer is the ? molecule, which consists of a glycerol molecule attached to three fatty acids.
triglyceride
? are similar to triglycerides except that one fatty acid is replaced with a phosphate group. The phosphate group is polar and the fatty acid chains are nonpolar. This allows for the formation of ? (lipid bilayer) through ? and ? interactions.
Phospholipids, plasma membranes, hydrophobic, hydrophilic
? are also lipids that are derived from cholesterol.
Steroids
? is an important component of plasma membranes.
Cholesterol
? perform a number of functions in the human body. They are an important structural component such as keratin for hair and nails, as well as collagen for muscles and organs.
proteins
The monomer of protein is the ?, in
which there are 20 different kinds.
amino acid
? are formed from the combination of two amino acids, and ? (polymers) are long chains of amino acids.
Dipeptides, polypeptides
large polymers of the nucleotide monomer.
Nucleic acids
consists of a pentose sugar, phosphate group, and one of five nitrogenous bases. The bases include adenine, thymine, guanine, cytosine, and uracil.
nucleotide
the nucleic acid that stores the genetic code through adenine/thymine bonds and guanine/cytosine bonds. It is a double helix in structure with deoxyribose sugars.
DNA
a single strand nucleic acid that translates the genetic code into proteins.
RNA
a test for simple carbohydrates such as glucose or maltose. very common test to detect reducing sugars (a sugar with a free aldehyde or ketone group)
Benedict’s Test
Benedict’s Test:
A ? result for sugar will leave you with a blue color. A ? result after boiling will result in a green color indicating a ? presence of sugar to a red color indicating a ? presence of sugar.
negative, positive, slight, large
a test for a complex carbohydrate such as starch
Lugol’s Iodine Test (IKI)
? in the form of Lugol’s solution will react with starch to form a deep blue to black color. ? gives a red-brown color. ? and ? do not react. The yellow to brown coloration of the testing solution indicates a ? result.
Iodine, Glycogen, Cellulose, small mono or disaccharides, negative
a simple method of detecting two or more peptide bonds
Biuret Test
Biuret Test:
When ? a violet to pink color will be seen. A ? result is the light blue coloration of the testing solution.
present, negative
used to test for the presence of sodium chloride (NaCl)
Silver nitrate (AgNO3)
Silver nitrate (AgNO3) test: A ? indicates the presence of silver chloride (AgCl) which is formed by the reaction of silver nitrate with sodium chloride.
white precipitate or cloudiness
In a solution, the amount of substance (mol) of solute divided by the mass (kg) of the solvent.
Molality
An indirect measurement of the solute concentration. It is strictly an experimental measurement relative to the system, in which the osmotic pressure measured is the force that would have to be exerted to prevent osmosis
Osmotic pressure
A solution that has a lower solute concentration than that of the cell and will cause swelling and eventual lysis of the cell.
Hypotonic
A solution is isotonic if the cell in contact does not swell or shrink.
Isotonic
A solution that has a higher solute concentration than that of the cell.
Hypertonic
a secondary active transport in which the molecule or ion is moved in the same direction as sodium. Also known as cotransport.
Symport
a secondary active transport in which the molecule or ion is moved in the opposite direction as sodium. Also known as countertransport.
Antiport
Factors that affect the rate of diffusion
1) The greater the concentration difference, the faster the rate of diffusion.
2) The higher the temperature, the faster the rate of diffusion.
3) The smaller the molecule, the faster the rate of diffusion.
Why isn’t glucose stored in cells rather than glycogen?
To preserve the diffusion gradient. Reduce the number of particles to reduce water uptake.
