CB Lab Final Exam

genetic engineering

the process by which an organism’s dna is purposely altered

recombinant dna technology

dna from different sources is combined in a single organism

transgenic

contains a gene from a foreign source

gene

a unit of dna that is associated with an inherited characteristic; typically codes for a specific protein, which is associated with a particular function in a cell or organism

restriction enzymes

cut dna at specific sites, and thus can be used to remove a gene from and organism’s dna

gene therapy

a technique in which a corrected version of the gene is delivered to cells containing the defective gene

meiosis

two sequential cell divisions that result in the reduction of the chromosome number to one-half

haploid cells

ones in which the chromosomes are not is pairs

diploid cells

one in which chromosomes are present in pairs

homologous chromosome

a pair of chromosomes bearing the same genes

sister chromatid

chromosomes composed of two genetically identical units

dyads/univalents

double chromosomes

tetrad/bivalents

composed of four chromatids formed by synapsis

chiasmata

word for cross over

synapsis

the formation of a close association between homologous chromosomes during prophase I

law of segregation

**paired unit factors (i.e., genes) segregate equally into gametes such that offspring have an equal likelihood of inheriting any combination of factors**

secondary spermatocytes

two daughter cells are formed to be this in the male

secondary oocytes

one daughter nucleus forms this

phenotype

the physical characteristic displayed by certain genotype

allele

are different “versions” of a specific gene, and they can be dominant or recessive with respect to each other

dominant

whenever present in a zygote, it will be the message that is expressed phenotypically

recessive

two copies of it must be present if it is to be expressed phenotypically

heterozygous

when there is a dominant and recessive allele present

homozygous recessive

when there are two recessive alleles present

homozygous dominant

when there are two dominant alleles present

polygenic traits

 traits that are controlled by multiple genes instead of just one

monohybrid cross

a cross between two true-breeding parents that express different traits for only one characteristic

dihybrid cross

a cross between two true-breeding parents that express different traits for two characteristics

law of independent assortment

genes do not influence each other with regard to sorting of alleles into gametes; every possible combination of alleles is equally likely to occur

codominance

type of inheritance in which two versions (alleles) of the same gene are expressed separately to yield different traits in an individual

incomplete dominance

where neither allele is completely dominant to the other and heterozygous display and intermediate phenotype

sex linked traits

traits located on the x chromosome

evolution

**the change in gene frequencies in a population over time**

variation

**the variety of alleles in a population**

heritable

your traits are programmed in your genetic makeup and because of the process of meiosis; your genetic makeup is derived from your parents

mutation

**a permanent variation in the nucleotide sequence of a genome**

crossover

(also, recombination) the exchange of genetic material between homologous chromosomes resulting in chromosomes that incorporate genes from both parents of the organism forming reproductive cells

selective pressures

environmental conditions that select for certain characteristics of individuals and select against other characteristics

zygote

the combination of mother’s egg cell and father’s sperm cell

genetic drift

the process of random change, controlled mostly by chance

natural selection

the environment is selecting who get to pass on their “good genes” to the next generation

population

all the members of the same species that live in one locale

gene pool

all of the alleles carried by all of the individuals in the population

ecology

a broad discipline that can be defined as the relationship between organisms and their environment

biotic

living components in an environment

abiotic

nonliving components in an environment

ecosystem

includes all of the organisms that live within an area and the physical environment in which they interact

food chain

a simple, linear map that shows the predation activity when only one type of organism is consumed by the organism on the next level

food web

**a web of trophic (feeding) relationships among producers, primary consumers, and higher level consumers in an ecosystem**

species diversity

the number of species and abundance of each species that live in a particular location

keystone predator

a type of species that is usually a predator that can control the population and distribution of prey species

adaptation

a heritable trait or behavior in an organism that aids in its survival in its present environment

allele frequency

how common an allele, or a variant form of a gene, is in a population

biogeography

**the branch of biology that deals with the geographical distribution of plants and animals**

bottleneck effect

the magnification of genetic drift as a result of natural events or catastrophes

convergent evolution

an evolution that results in similar forms on different species

differential reproductive success

A situation in which some individuals leave more offspring in the next generation than do others

fitness

an organism’s success in producing viable offspring

founder effect

a magnification of genetic drift in a small population that migrates away from a large parent population carrying with it an unrepresentative set of alleles

gene flow

the flow of alleles in and out of a population due to the migration of individuals or gametes

gene frequency

the relative frequency of an allele at a particular locus in a population, expressed as a fraction or percentage

genetic equilibrium

a condition in which the frequency of alleles or genotypes in a population does not change from generation to generation

genetic load

decrease in fitness of a population due to the presence of deleterious genes or genotypes in the gene pool

genotype frequency

number of individuals with a given genotype divided by the total number of individuals in the population

homologous structure

a structure that is similar because of descent from a common ancestor

inheritance

 **passing on of genetic traits from parents to offspring**

migration

the movement of individuals of a population to a new location; in population genetics it refers to the movement of individuals and their alleles from one population to another, potentially changing allele frequencies in both the old and the new population

mutagen

chemical or physical agent that can induce changes in DNA called mutations

directional selection

 a mode of **negative natural selection** in which an extreme phenotype is favored over other phenotypes, causing the allele frequency to shift over time in the direction of that phenotype

disruptive selection

a form of natural selection that favors extreme traits over intermediate traits

stabilizing selection

o**pposite of disruptive selection**. Instead of favoring individuals with extreme phenotypes, it favors the intermediate variants

radiometric dating

any technique used to date organic and also inorganic materials from a process involving **radioactive decay**

random mating

a population that randomly chooses their mate, rather than sorting between the adults of the population

trait

a variation in an inherited characteristic

vestigial structure

a physical structure present in an organism but that has no apparent function and appears to be from a functional structure in a distant ancestor

multiple allele traits

those in which there are more than two possible alleles for a trait

genetic engineering

The laboratory processes by which an organism's DNA is purposely altered are refered to as _____.

transgenic

An organism that contains a gene from a foreign source is referred to as:

gene

The unit of DNA that codes for a specific protein associated with a paricular function in a cell or organism is called a _____. 

Humulin

Originally produced in 1982 by Eli Lilly pharmaceutical company, _____ was the first genetically engineered pharmaceutical and a major advance in the treatment of diabetes.

GMOs dont have to be labeled because you cant telll if its been engineered or not

What is/are the regulation(s) enforced by the FDA regarding labeling of genetically altered foods and what is the reason for this policy? 

allergic reactions

According to the FDA, what are the health risks associated with the use of genetically altered foods?

the bacterium bacillus thuringiensis

The original source of the Bt gene was a:

plasmid

Small, circular pieces of DNA commonly found in *E. coli* and other bacteria are referred to as _____.

gene therapy

The general techniques of _____ deliver a corrected version of a gene to cells containing the defective version of the same gene.

x

The genes for sex-linked traits are typically located on the _____chromosome.

2

In a simple dominant/recessive trait, a recessive allele is expressed only when _____ copies of the allele are present in an individual organism’s genome.

3

In a monohybrid cross, there are potentially _____ different genetic combinations in the offspring with regards to the trait in question.

it seperates 2 sister chromatids to make 4 haploid cells

Meiosis I reduces the diploid chromosome set.  What role does meiosis II play in gamete formation?

crossing over

Sometimes a segment of DNA breaks off from a chromosome and trades places with a segment on its homologous chromosome.  This type of chromosomal structure change is called ____.

19

If the diploid number for house cats is 38, how many chromosomes are present in the egg cells they produce?

46

How many molecules of DNA are present in each daughter cell at the end of meiosis I in humans?  (Hint:  At the end of meiosis I, each daughter cell has 23 *replicated* homologues.)

alleles

Alternative versions of a gene for a given trait are called _________.

heterozygous

If ***A*** and ***a*** are two alleles of the same gene, then individuals who are ***Aa*** are said to be ___________.

codominance

When the phenotypes controlled by two alleles are equally displayed in the heterozygote, the two alleles are said to show __________.

genetic drift

The change in frequency of alleles in a population due to chance occurrences in a population is called _____.  These chance occurrences have greater effect in smaller populations.

genotype

The _____ of an organism is its genetic blueprint.  It is the particular combination of genes present in that organism.

evolution

When there is change in allele frequency within a gene pool, and the frequency change is accompanied by a corresponding phenotypic change in a species over time, _____ has occurred.

mutations

Slight changes in genes are called _________.  These are heritable (can be passed on) to offspring.  They are extremely important because they promote variability in the population.

population

A _____ is all the members of one particular species that live and reproduce in one locale.