MATERIAL AFTER EXAM 2

Which correctly describes F factors?

"F factor" is short for "fertility factor". If present, that cell can act as a donor. After it is transferred by conjugation, the recipient cell becomes F+.

Bottleneck effect

-loss of alleles due to genetic drift -population size reduced to a few individuals -an example is the cheetah population -results in loss of genetic diversity -small population increases probability of losing alleles -usually due to catastrophic event

Founder effect

-loss of alleles due to genetic drift -population started by a few members of another population (colony) -an example would be the Old Order Amish -small population increases probability of losing alleles -usually due to geographical event

Bacterial Transduction order of events

1. Phage infects bacterial cell. 2. Host DNA is hydrolyzed into pieces, and phage DNA and proteins are made. 3. Phages assemble; occasionally a phage carries a piece of the host cell chromosome. 4. New phages are released by bacterial cell lysis. 5. Transducing phage injects foreign DNA into a new recipient cell. 6. The transduced foreign DNA is recombined into the chromosome of the recipient cell.

In a given population of Drosophila, curly wings (c) is recessive to the wild-type condition of straight wings (c+). You isolate a population of 35 curly winged flies, 70 flies that are heterozygous for straight wings, and 45 that are homozygous for straight wings. What is the frequency of alleles in this population?

46.7% c; 53.3% c+

Which of the following is an example of a palindromic DNA sequence? (identical if read forward/backwards)

5' - CTGCAG - 3' 3' - GACGTC - 5'

Mapping of bacterial genes often involves data from both conjugation and transduction experiments. ______ may be used to determine the relative order and distance of genes that are far apart along the chromosome. _____ is useful in that it can provide fairly accurate mapping data for genes that are close together.

Conjugation; Transduction

3. Enzyme which attaches a methyl group to the number 5 position of the cytosine base, forming 5-methylcytosine.

DNA methyltransferase

Images representing spontaneous mutations

Depurination Deamination Tautomeric shift

DNA methylation activates gene expression.

False

The sum of all of the values for a trait, divided by the total number of individuals, is called the standard deviation.

False

During conjugation, one gene (A) is found to transfer to the recipient bacteria 26 minutes following the start of conjugation, while a second gene (M) is found to transfer 37 minutes following the start of conjugation. A third gene (T) transfers 45 minutes following the start of conjugation. Based on this information, which of the following is true?

Genes A and M have a genetic distance of 11 minutes. Genes A and T have a genetic distance of 19 minutes. Genes M and T have a genetic distance of 8 minutes. The order of the genes is A M T.

Who was the first to discover the process of natural transformation?

Griffith

2. Enzymes which acetylate the positively charged lysines within the core histone proteins.

Histone acetyltransferases

1. The pattern of histone modification acts much like a language or code in specifying alterations in chromatin structure.

Histone code hypothesis

6. Hemimethylated DNA is recognized by DNA methyltransferase, which makes it fully methylated.

Maintenance methylation

In horizontal gene transfer, DNA can be acquired from the same species or from a different species.

TRUE

It is often convenient to display measurements of continuous trait as a frequency distribution.

True

Silent mutations are possible due to the degenerate nature of the genetic code.

True

The mutation rate is the likelihood that a gene will be altered by a new mutation.

True

The variation seen in newborn birth weight is an example of a continuous quantitative trait.

True

Which procedure is used to identify a specific protein within a mixture of many different protein molecules?

Western blotting

The most common form of methylation is __________________

maintenance methylation.

Conjugation, transduction and transformation

prokaryotic gene transfer

A _________ is a normal cellular gene that through a ____________ mutation becomes an oncogene.

proto-oncogene, gain-of-function

Which process uses a bacteriophage as an intermediary for the genetic information?

transduction

The enzymes that add the methyl groups are known as _______________________

DNA methyltransferases.

5. The methylation of DNA that was previously unmethylated.

De novo methylation

Traits that fall into discrete categories are called continuous traits.

False

What is the difference between genetic testing and genetic screening?

Genetic testing is concerned more with individuals and genetic screening is concerned with populations.

When an F factor integrates into the chromosome, it creates

a high frequency of recombination (Hfr) cell.

Allelic frequencies can change due to selection or they may change due to ______________.

genetic drift

The process of natural selection relies on the presence of __________________ of a gene within a population.

multiple alleles

Vector DNA contains a DNA sequence, known as a(n) ______________________________, that is recognized by the replication enzymes of the host cell and allow it to be replicated.

origin of replication

4. Proteins which bind methylated sequences.

Methyl-CpG-binding proteins

A translocation that moves a gene from an area of euchromatin to heterochromatin would typically cause _____ in the expression of the gene.

a reduction

Caspases are active during which of the following?

apotosis (cell death)

Increase or decrease in the number of repetitive sequences

changes in repetitive sequences

Chromosome structure changed by deletion, duplications, inversions, translocations or there is a change in ploidy

chromosome structure and number

DNA transfer via a physical connection between two bacteria is known as

conjugation

During ________________ one bacterium acts as a donor and transfers genetic material to a recipient cell.

conjugation

Recombination to produce new combinations of alleles

crossing over

In eukaryotes, methyl groups are added to the________ residues.

cytosine

The conversion of cytosine to uracil in DNA is an example of _____.

deamination

A ________________ mutation decreases the chances of survival and reproduction. The extreme example of a deleterious mutation is a ________ mutation, which results in death to the cell or organism. On the other hand, a ____________ mutation enhances the survival or reproductive success of an organism. Some mutations are called ___________ mutations because they affect the phenotype only under a defined set of conditions.

deleterious lethal beneficial conditional

The complete loss of either a guanine or adenine from DNA is an example of _____.

depurination

An example of personalized medicine would be

determining the CYP2C9 alleles present to help set the patient's coumarin dose.

The selection of two or more phenotypes is known as ___________________.

disruptive selection

Natural selection is the process by which organisms with the best adapted phenotype are selected for by _______________.

environmental conditions

An epigenetic change that is passed from parent to offspring is said to show _______________________.

epigenetic inheritance

Exons of preexisting genes are rearranged to make a new combination

exon shuffling

Migration of a random few individuals from one population to a new area to establish a new population is an example of

founder effect.

Most commonly, when introduced into a cell, a cloned gene becomes integrated into the genome by nonhomologous recombination. This is known as __________________.

gene addition

Additional copies of a gene occur through misaligned crossing over

gene duplications

If the cloned gene is rendered inactive by mutation and replaces the normal gene, researchers can study how the loss of normal gene function affects the organism. This is called a ______________________.

gene knockout

If the genome of the host cell carries the same type of gene and if the cloned gene is swapped with the normal chromosomal gene by homologous recombination, then the cloned gene will replace the normal gene within the chromosome. This process is termed ____________________.

gene replacement

In DNA replication, the methylation pattern is _____________

heritable

Deleterious alleles may persist in the population particularly if they confer ________________________.

heterozygote advantage

Genes from one species introduced into another species

horizontal gene transfer

The residues that precede the _____________ genes are typically not methylated.

housekeeping

Independent segregation of different homologous chromosomes gives rise to new combinations of alleles

independent assortment

Methylation usually results in the __________ of transcription.

inhibition

Production of hybrid offspring

interspecies crosses

The term that indicates that cancer has begun to migrate to other parts of the body is ______.

metastatic

The units of genetic distance derived from bacterial conjugation studies are called _____.

minutes

What are the common types of mutations that occur to convert proto-oncogenes to oncogenes?

missense and amplifications (and translocation)

Point mutations, small deletions and insertions

new alleles

Which of the following is NOT an assumption of the Hardy-Weinberg equation? The population is large. There is no migration into or out of the population. There is nonrandom mating. There is no mutation in the gene being studied. There is no selection against a given genotype.

nonrandom mating

A quantitative trait follows a continuum means that

phenotypes are continuous and do not fall into discrete categories.

Most vectors are ______________, which are small circular pieces of DNA.

plasmids

If a gene has more than one allele and each allele has a frequency that is less than 99%, then the gene is considered to be

polymorphic

Epigenetics refers to the phenomenon where traits can be inherited through _____________ changes in DNA.

reversible

Label the figure with the appropriate label. homologous vs nonhomlogous recombination

see pic in book

Vector DNAs often contain resistance genes that provide host bacteria with the ability to grow in the presence of a toxic substance. Such a gene is called a __________________, because the expression of the gene selects for the growth of the bacterial cells.

selectable marker

Which of the following is NOT an assumption of the Hardy-Weinberg equation? There is no migration into or out of the population. Individuals of the population mate randomly. There is no mutation occurring in the population. The population size is very large. Selection is favoring the dominant allele.

selection favoring dominant allele

Genetic drift has the greatest influence on allele frequencies for which population size?

small

In the equation p2 + 2pq + q2 = 1, what does the term 2pq represent?

the genotypic frequency of heterozygous individuals

During _____________ a virus infects a bacterium and then transfers some bacterial genetic material from that bacterium to another.

transduction

During _____, a portion of a bacterial chromosome is transferred to a recipient cell via a _____.

transduction; bacteriophage

During ____________ a living bacterial cell picks up genetic material from the environment.

transformation