Lab 1

Question 1

In homeostatic control (thermostat in a room), the event or factor being controlled is the

Answer 1

variable, X (room temperature)

Question 2

variable, X (room temperature) is maintained within a narrow limit around a

Answer 2

set point (level or range, the temperature at which you have set the thermostat)

Question 3

A ? analyzes the information received from ? and determines a response, which is carried out by ?

Answer 3

1. control or integrating center (the thermostat)
2. sensors (temperature sensors)
3. effectors (furnace or air conditioner)

Question 4

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 ?.

Answer 4

1. sensor or receptor
2. an afferent pathway
3. control center (usually the hypothalamus or midbrain)
4. set point
5. effector
6. efferent pathway

Question 5

occurs when a change in a variable triggers a response which adjusts in the opposite direction of the initial change

Answer 5

negative feedback

Question 6

fluctuations constantly occur above or below a set point

Answer 6

dynamic constancy

Question 7

the average value of the range of the variable

Answer 7

set point

Question 8

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.

Answer 8

1. sensitivity
2. antagonistic effectors
3. two sensors and two effectors

Question 9

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.

Answer 9

Positive Feedback

Question 10

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 ?.

Answer 10

1. thermoreceptors
2. afferent sensory pathways
3. posterior hypothalamus (integrating center)
4. efferent autonomic pathways
5. sweat glands
6. smooth muscles in arterioles (effectors).

Question 11

occurs when strenuous exercise or high environmental temperatures cause the body’s homeostatic mechanisms to be overtaxed

Answer 11

Heat exhaustion

Question 12

can follow heat exhaustion if the regulatory center in the hypothalamus fails due to continued high body temperature

Answer 12

Heat stroke

Question 13

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.

Answer 13

1. thermoreceptors, afferent pathways, hypothalamus, and efferent pathways
2. arterioles
3. sympathetic nervous system
4. nonshivering thermogenesis
5. efferent somatic nervous system

Question 14

The ? and glucagon have an opposite effect on maintaining blood glucose levels.

Answer 14

antagonistic effectors insulin,

Question 15

When blood glucose levels rise (after a meal) ? is released from the beta cells of the pancreatic islets.

Answer 15

insulin

Question 16

? is released from pancreatic alpha cells in response to low blood sugar.

Answer 16

Glucagon

Question 17

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 ?.

Answer 17

gluconeogenesis

Question 18

The four classes of organic molecules

Answer 18

carbohydrates, proteins, lipids, and nucleic acids

Question 19

Each class of organic molecules is composed of a small organic subunit called a ?, which can combine to form a ?.

Answer 19

monomer, polymer

Question 20

? 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.

Answer 20

Condensation synthesis, Hydrolysis

Question 21

simple sugar monomers found in carbohydrates

Answer 21

Monosaccharides

Question 22

two sugars linked together

Answer 22

Disaccharides

Question 23

long chains of glucose molecules, forming a polymer

Answer 23

Polysaccharides

Question 24

straight chain of glucose with very few branches found in plants

Answer 24

polysaccharide starch

Question 25

highly branched chain of glucose found in animals (used as energy storage)

Answer 25

Glycogen

Question 26

the primary constituent of plant cell walls, which is indigestible by humans. We refer to this material as fiber.

Answer 26

Cellulose

Question 27

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

Answer 27

Lipids

Question 28

The monomer of a lipid is the ?. It is a long chain of carbon and hydrogen with a carboxyl group at one end.

Answer 28

fatty acid

Question 29

have no double bonds in the chain, which means they have a maximum number of hydrogen (found in animal fats)

Answer 29

Saturated fatty acids

Question 30

? have double bonds in the carbon chain, which means less hydrogen (found in plant oils).

Answer 30

Unsaturated fatty acids

Question 31

The polymer is the ? molecule, which consists of a glycerol molecule attached to three fatty acids.

Answer 31

triglyceride

Question 32

? 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.

Answer 32

Phospholipids, plasma membranes, hydrophobic, hydrophilic

Question 33

? are also lipids that are derived from cholesterol.

Answer 33

Steroids

Question 34

? is an important component of plasma membranes.

Answer 34

Cholesterol

Question 35

? 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.

Answer 35

proteins

Question 36

The monomer of protein is the ?, in | which there are 20 different kinds.

Answer 36

amino acid

Question 37

? are formed from the combination of two amino acids, and ? (polymers) are long chains of amino acids.

Answer 37

Dipeptides, polypeptides

Question 38

large polymers of the nucleotide monomer.

Answer 38

Nucleic acids

Question 39

consists of a pentose sugar, phosphate group, and one of five nitrogenous bases. The bases include adenine, thymine, guanine, cytosine, and uracil.

Answer 39

nucleotide

Question 40

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.

Answer 40

DNA

Question 41

a single strand nucleic acid that translates the genetic code into proteins.

Answer 41

RNA

Question 42

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)

Answer 42

Benedict’s Test

Question 43

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.

Answer 43

negative, positive, slight, large

Question 44

a test for a complex carbohydrate such as starch

Answer 44

Lugol’s Iodine Test (IKI)

Question 45

? 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.

Answer 45

Iodine, Glycogen, Cellulose, small mono or disaccharides, negative

Question 46

a simple method of detecting two or more peptide bonds

Answer 46

Biuret Test

Question 47

Biuret Test: | When ? a violet to pink color will be seen. A ? result is the light blue coloration of the testing solution.

Answer 47

present, negative

Question 48

used to test for the presence of sodium chloride (NaCl)

Answer 48

Silver nitrate (AgNO3)

Question 49

``` Silver nitrate (AgNO3) test: A ? indicates the presence of silver chloride (AgCl) which is formed by the reaction of silver nitrate with sodium chloride. ```

Answer 49

white precipitate or cloudiness

Question 50

In a solution, the amount of substance (mol) of solute divided by the mass (kg) of the solvent.

Answer 50

Molality

Question 51

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

Answer 51

Osmotic pressure

Question 52

A solution that has a lower solute concentration than that of the cell and will cause swelling and eventual lysis of the cell.

Answer 52

Hypotonic

Question 53

A solution is isotonic if the cell in contact does not swell or shrink.

Answer 53

Isotonic

Question 54

A solution that has a higher solute concentration than that of the cell.

Answer 54

Hypertonic

Question 55

a secondary active transport in which the molecule or ion is moved in the same direction as sodium. Also known as cotransport.

Answer 55

Symport

Question 56

a secondary active transport in which the molecule or ion is moved in the opposite direction as sodium. Also known as countertransport.

Answer 56

Antiport

Question 57

Factors that affect the rate of diffusion

Answer 57

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.

Question 58

Why isn't glucose stored in cells rather than glycogen?

Answer 58

To preserve the diffusion gradient. Reduce the number of particles to reduce water uptake.