Biology Exam 4

Question 1

What does PCR stand for?

Answer 1

Polymerase chain reaction

PCR amplifies DNA sequences.

Question 2

How does PCR work?

Answer 2

In a thermocycler, DNA is denatured, and Taq polymerase adds nucleotides using separated strands as templates.

Question 3

How can PCR be used in criminal cases?

Answer 3

Creates multiple copies of DNA sequences, making it easier to work with.

Question 4

What is DNA profiling?

Answer 4

A technique using differences in DNA sequences to positively identify individuals.

Question 5

What are STRs?

Answer 5

Short tandem repeats, 13 DNA sequences carried by all humans.

Question 6

How has DNA profiling contributed to the exoneration of individuals?

Answer 6

Positively identifies suspects using DNA.

Question 7

What is gel electrophoresis?

Answer 7

Separation of DNA fragments by size using an electric current.

Question 8

How does gel electrophoresis work?

Answer 8

Copied STRs are added to agarose gel, and an electric current is applied; smaller fragments move more quickly.

Question 9

What is implicit bias?

Answer 9

A subconscious framework affecting feelings based on physical observations.

Question 10

How can implicit bias impact a jury member?

Answer 10

It can lead to wrongful convictions.

Question 11

What is gene expression?

Answer 11

Parts of the genome (DNA) being physically shown.

Question 12

What occurs during transcription?

Answer 12

DNA is converted to RNA in the nucleus.

Question 13

What is the role of RNA polymerase in transcription?

Answer 13

Binds to the promoter region, unwinds DNA, and ties RNA nucleotides with complementary DNA nucleotides.

Question 14

What occurs during translation?

Answer 14

RNA is converted to protein at ribosomes.

Question 15

How does tRNA function in translation?

Answer 15

Matches its anticodon with codons on the mRNA and attaches amino acids.

Question 16

What is the central dogma theory?

Answer 16

DNA encodes proteins through transcription and translation.

Question 17

What is a mutation?

Answer 17

Changes in genetic sequences.

Question 18

What is a substitution mutation?

Answer 18

Substitution of one base for another.

Question 19

What is a frameshift mutation?

Answer 19

Addition or deletion of a base affecting the reading frame.

Question 20

Why are some genes expressed in some cell types but not others?

Answer 20

Cells express different genes based on their functions.

Question 21

What is cloning?

Answer 21

Making copies of the same gene.

Question 22

How is cloning used in bacteria?

Answer 22

By inserting a gene into a plasmid to be reinserted back into the bacteria.

Question 23

What is rBGH?

Answer 23

Recombinant bovine growth hormone.

Question 24

How is rBGH milk made?

Answer 24

Genes with altered rBGH are inserted into the cow.

Question 25

What are GMOs?

Answer 25

Genetically modified organisms.

Question 26

What are concerns regarding GMOs?

Answer 26

Interactions with wild populations and competition.

Question 27

What are stem cells?

Answer 27

Unspecialized, undifferentiated precursor cells with an undetermined function.

Question 28

What is gene therapy?

Answer 28

Replacement of defective genes with functional genes.

Question 29

What is biological evolution?

Answer 29

Process by which organisms change over generations through variations in traits and natural selection.

Question 30

What are nonevolutionary changes?

Answer 30

Changes due to short-term environmental factors that are not genetic.

Question 31

What is the theory of common descent?

Answer 31

The theory that all living organisms share a common ancestor.

Question 32

What do phylogenetic trees illustrate?

Answer 32

How different species are related through one common ancestor.

Question 33

What influenced Darwin's theory of evolution?

Answer 33

Collection of diverse animals and plants, Principles of Geology, divergence between island organisms and mainland species.

Question 34

What is the Linnean system?

Answer 34

A classification system based on shared traits and evolutionary relationships.

Question 35

What are the major domains of life?

Answer 35

* Bacteria * Archaea * Eukarya

Question 36

What is anatomical homology?

Answer 36

Similarities in skeletal bone structures.

Question 37

What is convergent evolution?

Answer 37

Structural similarities in unrelated species with relevant lifestyles.

Question 38

What are vestigial traits?

Answer 38

Nonfunctional or greatly reduced traits.

Question 39

What is biogeography?

Answer 39

The distribution of species on Earth.

Question 40

What is radiometric dating?

Answer 40

Using ratios of radioactive elements to estimate the age of rocks.

Question 41

Why is the theory of evolution the best explanation for the origin of humans?

Answer 41

It is well-supported by a wide variety of evidence, including anatomy, geology, molecular biology, and genetics.

Question 42

What is the biological species concept?

Answer 42

A group of individuals that can interbreed and produce fertile offspring.

Question 43

What is reproductive isolation?

Answer 43

Prevention of gene flow between species.

Question 44

What are pre-fertilization barriers?

Answer 44

Barriers that prevent fertilization from occurring.

Question 45

What is spatial reproductive isolation?

Answer 45

Individuals from different species do not come in contact with each other.

Question 46

What is hybrid inviability?

Answer 46

Zygote cannot complete development due to incomplete genetic instructions.

Question 47

What are the three steps of speciation?

Answer 47

* Isolation of gene pools * Evolutionary changes in gene pools * Evolution of reproductive isolation

Question 48

What is the evidence that modern humans arose in Africa?

Answer 48

Humans have less genetic diversity than other great apes, and African populations have the greatest genetic diversity.

Question 49

What is genetic drift?

Answer 49

Change in allele frequency due to chance.

Question 50

What is the founder effect?

Answer 50

Genetic differences resulting when a small sample begins a new population.

Question 51

What is sexual selection?

Answer 51

When a trait influences the likelihood of mating.

Question 52

What is assortative mating?

Answer 52

Preference to mate with someone similar (e.g., height).

Question 53

What is adaptive radiation?

Answer 53

Rapid diversification of some species into a large and varied group of descendant species.

Question 54

Why are viruses considered nonliving?

Answer 54

They cannot maintain homeostasis and are incapable of growth or reproduction without assistance.

Question 55

How are evolutionary classifications of living organisms created?

Answer 55

Using phylogeny and cladistic analysis.