Final Exam: Other Sections Review

Question 1

Homeostasis

Answer 1

processes by which tissues maintain normal function

Example: pH of O2, glucose
Example: temperature of body

Body has particular ranges – depending on what is being discussed – give optimal function for parts of the body

Question 2

Negative Feedback

Answer 2

MOST COMMON WAY TO MAINTAIN HOMEOSTASIS!

stimulus receives deviation from setpoint

sensor constantly monitors conditions

integrating center compares conditions to a set point, based on a desired value

effector cause changes to compensate for deviation

response: move system towards set point

Question 3

Example of Negative Feedback

Answer 3

Thermoregulation

Sensors in body to determine if body is too cold or warm
* Integrator compares condition
* If effector determines cold, dog shaking can occur

o Hair contracts to skin to hold in more air pockets to contain warmth
* If effector determines warm, a dog will pant
o Hair raised to let in air pockets

Question 4

Positive Feedback

Answer 4

Can enhance a change(delta), big event, a reset(then starts over)

Examples: childbirth, ovulation, immune responses

Question 5

Autocrine signals

Answer 5

• Act on the same cell that secretes them
• EX: thirsty, drink water

hydrophilic

Question 6

paracrine signals

Answer 6

Diffuse locally and act on nearby cells
Nonspecific, do not get to choose what it acts on

Ex: someone else thirsty, throw water at them

hydrophilic

Question 7

Endocrine signals

Answer 7

Hormones carried between cells by blood or other body fluids

Find target cell, bind to receptor, causes a change; Local or distant (in blood, going ALL OVER body!)

Nonspecific
EX: people are thirsty, set off sprinkler

hydrophilic or lipophilic depending on the specific hormone, some hormones like steroids are lipophilic while others like proteins and peptides are hydrophilic

Question 8

Neural signals

Answer 8

Neurotransmitters diffuse a short distance between neurons

Local or distant

VERY specific, decide which cells receive message

EX: someone across room is thirsty, fire a nerf super soaker at them lol

hydrophilic (neurotransmitters are usually hydrophilic)

Question 9

Neuroendocrine signals

Answer 9

Neurohormones are hormones released from neurons, In posterior pituitary

hydrophilic or lipophilic depending on the specific hormone, some hormones like dopamine and norepinephrine are hydrophilic, while others like cortisol and thyroid hormone are lipophilic

Question 10

Hydrophilic

Answer 10

mixed in or dissolves in watter; wet material by water

Question 11

lyophilic

Answer 11

not easily dissolved in solvent

Question 12

Three classes of signaling molecules

Answer 12

protein based, amino acid derivatives, and steroids

Question 13

protein based signaling molecules

Answer 13

(peptide, polypeptide)
o Molecule made of amino acids, held together by peptide bonds
o Example: Secretin is chemical messenger
o Bind to receptors on surface of target cell, since not lipid soluble (hydrophilic ligands!)

Question 14

Amino acid derivative signaling molecules

Answer 14

o Ex: epinephrine, one amino acid long; not lipid soluble
o Most not lipid soluble; bind to surface receptors on surface of target cell

Question 15

Steroid signaling molecules

Answer 15

o ALL lipid soluble; can bind to receptors inside target cell
o Hydrophobic!
o All structures based on cholesterol structure! Example with four yellow blocks/carbons are base/cholesterol
o Example given: Cortisol

Question 16

Mendel’s 1st Law: Law of segregation

Answer 16

two different alleles segregate from each other during meiosis (Separation of homologous chromosomes pairs in meiosis I)

Chromosome Theory of Inheritance: Genes are located on chromosomes, each at a particular gene locus

Mendel’s Principle of Segregation – the physical basis for the segregation of Mendel’s traits is the separation of alleles when homologous chromosomes pairs are separated in Meiosis I

Question 17

Mendel’s 2nd Law: Independent Assortment

Answer 17

Because two genes are usually located on separate chromosomes, they sort independently of each other during meiosis

Example: seed color and seed shape do not predict the other

Genes on the same chromosome are likely to be linked and do not separate during meiosis

Linked genes can be separated by crossing over events!!

Question 18

Exceptions to Mendel’s Laws

Answer 18

o Made assumptions based upon work
 No environmental influences
 Alleles are “either/or”
 “factors” act independently of one another and don’t interact
* Certain parts of plants would change but others would be left alone/not influenced
o However, these assumptions don’t apply to many traits!

Continuous variation in quantitative traits, incomplete dominance, codominance, pleiotropic effects, and environmental effects

Question 19

Continuous variation in quantitative traits

Answer 19

Polygenic Inheritance- the greater number of genes influencing a phenotype, the more continuous the distribution of phenotype

 Mendel state research as short or tall, but it is just not this way, it is continuous
 Important to note continuous can also show the continuum changing over time

Question 20

Incomplete dominance

Answer 20

 None of the alternate alleles are fully dominant or recessive

• Example: flowers
  o Pigment alleles not evenly distributed throughout flower, so cannot be “either/or” under Mendel’s principles

Question 21

Codominance

Answer 21

no single alleles is dominant, and each phenotype is distinctly present
 Example: A-B-O blood groups
* Can have a dominant allele or recessive allele, but MANY subtypes

Question 22

Pleiotropic effects

Answer 22

When an allele has more than one effect on the phenotype

Example: Marfan’s syndrome

Dominant mutation to TGF-beta, Overexpression of gene, Involved in forming many connective tissues, Leads to huge increase of this protein in those that have it, Genetic disorder of connective tissues

Question 23

environmental effects

Answer 23

Allele expression may depend on environment

Tyrosinase=pigment, Can be affected by temperature; Tyrosinase inactive at higher temperature, no pigment; Tyrosinase active at lower temperature, pigment

Example: cat