Exam 3 Practice

An individual with the genotype Aa is:

Heterozygous

In order for someone to express (show in their phenotype) a recessive trait, they must:

have two recessive alleles

Each gamete carries what number of alleles for each gene?

1

When there are more than two alleles for a gene (a seen in blood type) we call this a:

multiple allelic trait

What type of allele produces its effects in only homozygous individuals?

Recessive

A recessive allele is one:

Whose effect is masked by a dominant allele

Traits controlled by sex-linked recessive alleles on the X chromosome appear more often in males because:

males receive only one X, so a single recessive allele produces the trait.

The law of segregation states that ______________________ during gamete formation.

homologous chromosomes separate

There are 3 different alleles for blood type A, B, and O. Blood type is:

A multiple allelic trait

Codominance is a phenomenon that occurs in human blood types. Codominance is when:

Both of the alleles in a heterozygote are expressed phenotypically in an individual

When the information for an amino acid is found on mRNA it is called the:

codon

Which of the following is found in RNA but not in DNA?

Uracil

The process of converting the 'message' of mRNA into a sequence of amino acids is called:

translation

What type of RNA has a codon of bases that carries the sequence of amino acids in a protein? (It is a complimentary copy of a DNA strand.)

mRNA

Transcription is the process of

synthesizing a complimentary RNA molecule using a DNA template.

What type of RNA combines with proteins to form the building site of proteins.

rRNA

The first step of translation is _______________, when the ribosomal subunits come together with the mRNA and a tRNA carrying a methionine.

initiation

The information for a single amino acid is composed of ______ nucleotides.

3

mRNA is:

complementary to the DNA template strand

When DNA is replicated, each parent strand is used as a template and is bound to its respective new strand. This method of replication is called:

semi-conservative

What type of RNA carries specific amino acids to the ribosome to be used during protein synthesis?

tRNA

At the end of transcription there is a(n) ___________________________________ that causes the mRNA, DNA and RNA polymerase to detach from each other allowing the mRNA to move to the cytoplasm.

termination signal

We call a codon that tells where to start creating a protein:

a start codon

Which of the following is not a difference between RNA and DNA?

RNA has no phosphate, DNA has phosphate

Charles Darwin’s hypothesized mechanism for evolution is ______________________ in which individuals with certain inheritable traits will survive and reproduce better than those without the traits.

natural selection

The sum of all the alleles of all the genes in a population is called:

the gene pool

Horses and donkeys can mate successfully to produce mules, which are sterile. Which genetic isolating mechanism prevents horses and donkeys from becoming a single species?

hybrid infertility

Isolating mechanisms prevent interbreeding between species. Ecological isolation occurs when interbreeding is prevented by the use of different resources, and therefore habitats within the same general area. This often involves host specificity. What type of isolating mechanism is this?

pre-zygotic

Isolating mechanisms that prevent mating between species (no fertilization), are known as:

pre-zygotic isolating mechanisms

The Kaibab squirrel lives on the north rim of the Grand Canyon, and the Abert squirrel lives on the south rim. This is an example of:

geographical isolation

Gametic incompatibility is an example of

a pre-zygotic isolating mechanism.

Inbreeding is defined as:

sexual reproduction among closely related individuals

Traits that help individuals successfully reproduce in their current environment (as well as aiding directly in survival) are called:

adaptations

A group of interbreeding natural populations that is reproductively isolated from other such groups is called a

biological species

After a population bottleneck the remaining small population will have less variation in alleles than the original population. If the small population then grows in size and gets back up to the population size before the bottleneck, it will also increase the variation in its alleles.

False

A simple definition for evolution is:

descent with modification

When interbreeding is prevented by differences in the timing of activities, we call this:

temporal isolation.

The biological species concept relies on the concept of:

reproductive isolation

When a small isolated population is formed (often on an island) by a small number of individuals that may differ in alleles from the source population it is called:

the founder effect

Inbreeding can increase the incidence of__________________ which may increase the incidence of genetic defects (particularly recessives).

homozygotes

When two populations diverge when they are geographically separated from each other we call this:

allopatric speciation

Gametic incompatibility is important in species that:

scatter their gametes

Fossils that link different groups (i.e. land-dwelling mammals to whales) are called:

transitional forms

The adaptation of distantly related groups to similar selective pressures. Produces features with similar functions or even a superficial resemblance, is called:

convergent evolution

Which of the following is a form of evidence used to help determine evolutionary relationships between organisms?

Shared anatomical features.

In the scientific name Spongiforma squarepantsii, Spongiforma is what level of classification?

genus

A trait is ___________________ if it differs from the ancestral form.

derived

A phylogeny is:

the evolutionary history of an organism and its relatives

Which of the following is a form of evidence used to help determine evolutionary relationships between organisms?

Molecular evidence (shared genetic sequences).

A group that contains all the living descendants of a common ancestor is:

monophyletic