Bio 173 final

Question 1

Dependent variable

Answer 1

affected in response to the independent variable.
Ex. enzymatic activity of catalase

Question 2

Independent variable

Answer 2

Manipulated/ Changed by researchers
not changing

Question 3

positive controls

Answer 3

variable with known effect, expect a specific effect

Question 4

negative control

Answer 4

no treatment, control/placebo, no effect

Question 5

hypothesis

Answer 5

A testable statement that provides a possible explanation for a phenomenon. It is usually based on prior knowledge, observations, or theories.
Example: Catalase in potatoes requires Fe to function OR Fe is a cofactor for catalase.

Question 6

prediction

Answer 6

A prediction is a specific forecast about the outcome of a study or experiment based on a hypothesis. It states what you expect to happen if the hypothesis is correct. An if-then statement, of what you expect to observe if your hypothesis is true. “If the level of sunlight increases, then the rate of photosynthesis will increase, resulting in more oxygen production.”

Question 7

why are freezer stocks prepared

Answer 7

preserved the bacteria for longterm storage, used to make new probiotics during clinical trial

Question 8

three steps of each cycle in PCR

Answer 8

denaturation, annealing, extension

Question 9

PCR cocktail (master mix) component and functions of each

Answer 9

“Tiny primers need buffers too”

T - Taq Polymerase (heat-stable enzyme that extends DNA from the primers).
P - Pair for Primers (DNA or RNA to start DNA synthesis).
N - Nucleotides (building blocks of DNA).
B - Buffer (maintains pH for optimal enzyme activity).
T - Thermocycler (device to cycle temperatures and melt DNA)

Question 10

positive control in PCR

Answer 10

shows your setup works

Question 11

negative control in PCR

Answer 11

SHOULD have no result
if there is a result, contamination present - unwanted DNA in reagents or something is in your sample accidentally

Question 12

scientific method

Answer 12

Question→Hypothesis→Experiment→Data→Conclusion

Question 13

evolution and descent with modification

Answer 13

Change in genetic composition in a population over time (does not happen in an individual)

Question 14

natural selection

Answer 14

Changes in genetic composition and gene frequencies in a population over time favor one that is more advantageous, species with the specific gene frequency are more likely to survive and reproduce - making it more prominent in the gene pool and population. Advantageous variations will eventually accumulate in the population, and the less favorable will diminish.

Question 15

macroevolution

Answer 15

new life forms derived from older forms of life (birds from dinosaurs)

Question 16

Law of succession

Answer 16

living organisms in a region will resemble fossils in the SAME region - fossils will appear in layered strata (rocks) with predictable sequence all around the world

Question 17

anatomical homologs

Answer 17

structure that was evolutionarily derived from a single feature in an ancestor - an inherited PHYSICAL feature from an ancestor

Question 18

molecular homology

Answer 18

similarities between species on a DNA/molecular level from an ancestor

Question 19

convergent evolution

Answer 19

When organisms that are not closely related evolve similar behaviors or features, often as solutions to a common problem (similar body shapes, color patterns, behaviors)

Question 20

microevolution

Answer 20

occurs over generations, short time scales

Question 21

artificial selection

Answer 21

when humans take steps to amplify a “desirable trait” in animals and plants in future generations (like dog breeds, colors of flowers, scents of plants)

Question 22

antibiotic resistance in bacteria

Answer 22

Antibiotic resistance occurs when bacteria mutate, survive antibiotics, and multiply, making treatments ineffective—a major threat to humanity.

Question 23

vestigial structure

Answer 23

structures that have no apparent function and appear to be residual parts from a past ancestor (pelvic bone of a snake, our appendix and wisdom teeth)

Question 24

speciation

Answer 24

occurs when a group within a species separates from other members of its group (a physical barrier) and develops its own unique characteristics (genetic drift)

Question 25

sexual dimorphism

Answer 25

different characteristics in males and females - cause attraction and more mating success when a male is more sexually dimorphic (different colors, size)

Question 26

naming hierarchy of taxonomy

Answer 26

dear king Phillip came over for good soup

Domain Kingdom Phylum Class Order Family Genus Species

Question 27

taxonomy vs phylogeny

Answer 27

phylogeny is a hypothesis about evolutionary relationships (like an evolutionary tree), showing a pattern of descent not phenotypic similarities and taxonomy is classifying one organism

Question 28

ancestral vs derived characteristics

Answer 28

Ancestral - originated in an ancestor
Derived - developed in that organisms

Question 29

What is cladistics? How do you identify a clade in a phylogenetic tree?

Answer 29

shared characteristics to place a species into a group by class, ancestral species has descendents

Question 30

sister taxa

Answer 30

terminal clades that come from a common node that are considered closely related

Question 31

outgroups

Answer 31

species from an evolutionary lineage that is closely related to but not part of the group being studied (all have wings but outgroup)

Question 32

why is evolutionary science so controversial and misrepresented in the media

Answer 32

macroevolution implies that change over longterm time make people think that people came from monkeys (wrong) and that we are not the chosen ones and are not special

Question 33

interspecific

Answer 33

BETWEEN different species

Question 34

intraspecific

Answer 34

competition between the same species

Question 35

interference

Answer 35

Direct interaction where individuals actively impede each others growth
Ex. bacteria that produces antibiotics to kill off other types of bacteria

Question 36

exploitation

Answer 36

Indirect interaction, one individual affects the other by consuming the same resources over time
Ex. Plants taking up nutrients and space so that others cannot

Question 37

What treatments test intraspecific vs. interspecific competition?

Answer 37

Intraspecific competition: Tested in monocultures (100% of species A or B).
Interspecific competition: Tested in mixed cultures (all other treatments).

Question 38

What are the null and alternative hypotheses?

Answer 38

Null hypothesis (H₀): Assumes no effect or difference; any observed results are due to chance.
Alternative hypothesis (Hₐ): Assumes there is an effect or difference; results are not due to chance.

Question 39

Why do we run our PCR product on a gel?

Answer 39

Verify the amplification, confirming that PCR generated the expected product size

Question 40

How does the gel matrix separate different size DNA fragments?

Answer 40

Size based separation - longer DNA travels slower than shorter DNA

Question 41

Why does DNA move down the gel?

Answer 41

Starts at the negative electrode, moves TOWARD the positive electrode (DNA is negatively charged from its phosphate backbone)

Question 42

Interpret gel results using the DNA ladder and controls

Answer 42

Ladder - acts as a reference to estimate the size of PCR products
Positive control - confirms that the PCR and gel works as expected, produces a band at target size
Negative control - detects contamination, should not produce anything

Question 43

BLAST

Answer 43

A national database search tool that fields a best match

Question 44

What is a t-test?

Answer 44

Determines the significant difference in hypothesis testing

Question 45

P<0.05

Answer 45

statistically significant (reject H0)

Question 46

P>0.05

Answer 46

0.05 statistically insignificant (fail to reject H0)

Question 47

Pearson’s Correlation (r)

Answer 47

Strength between two variables, -1 to 1 where -1 is a perfect negative correlation and 1 is perfect positive correlation

Question 48

How is fiber fermented by the gut microbiome?

Answer 48

Bacteria break down fiber into smaller fatty acids for energy and produce gaseous byproducts.

Question 49

What are the end products of fiber fermentation in the gut?

Answer 49

Short-chain fatty acids (SCFAs) that provide energy.

Question 50

What are the gaseous byproducts of fiber fermentation?

Answer 50

Hydrogen (H₂), methane (CH₄), and carbon dioxide (CO₂).

Question 51

How do fermentation byproducts get absorbed into the bloodstream?

Answer 51

Gases like H₂, CH₄, and CO₂ are absorbed through the gut lining into the bloodstream

Question 52

How do byproducts of fermentation in the gut reach the lungs?

Answer 52

They are transported via the bloodstream to the lungs, where they diffuse and are exhaled in breath.

Question 53

Why do some people produce more methane gas in their breath?

Answer 53

They have a different gut microbiome composition with more methane-producing archaea/bacteria.

Question 54

What factors influence the composition of the gut microbiome?

Answer 54

Diet, genetics, health conditions, and environment.

Question 55

What type of microorganisms are responsible for methane production in the gut?

Answer 55

Methane-producing archaea or bacteria.

Question 56

interference vs exploitative competition

Answer 56

Interference Competition: Direct interaction where organisms block others from accessing resources (e.g., lions chasing hyenas from a kill).
Exploitative Competition: Indirect competition by depleting shared resources (e.g., plants competing for sunlight).

Question 57

parts of DNA not needed in PCR that need to be removed

Answer 57

Excess primers, dNTPs, longer DNA fragments, the original template strand