Genetics for Dummies Exam 1

Terms in this set (114)

examines how traits are passed from one generation to the next (in the form of genes in DNA)

Mendelian genetics (classical)

describes how physical characteristics are passed from one generation to the next. Ex: study of cells and chromosomes (sex and reproduction)

molecular genetics

the study of the chemical and physical structures of DNA, RNA and proteins; how genes do their jobs. Ex: muscle function, blood type, susceptibility to disease (physical and chemical structures of DNA)

population genetics

looks at the genetic makeup of larger groups. Ex: travel, isolation, mating choices, geography, behavior, evolution (inheritance patters of geographic location)

quantitative genetics

examines the statistical relationships between genes and the traits they encode; highly mathematical. Ex: running speed, dog's ability to retrieve, egg number in birds (how heritable a trait is)

transmission genetics

classical genetics; describes how traits are passed on (transmitted) by parents to their offspring

prepares, keeps supplies organized and stocked, cleaning, separates DNA

Graduate and post doctoral students

independent research, work for professors and writes dissertations

research scientists

work in private industries, designs experiments, supervise technicians

research scientist, but teach courses/get funds/write papers, supervises everyone

genetic counselor

interpret medical histories of patients and families, see what could be inherited

organisms whose cells lack a nucleus, therefore have DNA floating loosely in the liquid center of the cell

organisms that have a nucleus to house DNA

powerhouse of the eukaryotic cell; convert glucose to ATP

processes the energy of sunlight to sugars that plant mitochondria use to make energy

make up the cells of the body (specialized for specific functions) and produced by mitosis

cells used for reproduction (eggs and sperm) and produced by meiosis

sex chromosomes

chromosomes that determine gender (female - XX, male - XY)

autosomal chromosomes

chromosomes that are not sex chromosomes (humans have 44)

each specific point along the chromosome

the part of the chromosome that is pinched in and gives the chromosome its shape

individual chromosome on each identical (size, shape, and genes carried) pair

the end of chromosomes with densely packed DNA to protect the DNA message

alternative form of a gene which codes for physical traits (phenotype)

normal cell metabolism where DNA supervises work in the cell and it grows normally

synthesis (copying) of DNA

chromosomes condense, cell nucleus breaks up, chromosomes begin to move around the cell

chromosomes line up in the center of the cell, spindles attach chromosomes to poles

sister chromatids are pulled apart and move to opposite poles of the cell

nuclear membrane forms around separated chromosomes and chromosomes unravel

homologous chromosomes line up and exchange parts (crossing over/recombination), homologous chromosomes line up and homologs separate, cell divides and genetic material is reduced by half

individual chromosomes condense and line up, sister chromatids separate and move to opposite poles, cells divide, resulting in 4 daughter cells

two plants are crossed and the pollen from one can be used to fertilize the eggs of another

self pollination (selfing)

some flowers produce both flowers and pollen so the flower can fertilize its own eggs

when things get separated from each other; in terms of genetics - two alleles are separated, thus determining phenotype

two copies of each gene

one factor masks the presence of another

traits are masked by a dominant trait

law of independent assortment

every offspring has the same opportunity to inherit any allele at any other locus

when any individual with an unknown genotype is crossed with a true breeding individual with the recessive phenotype (homozygote)

multiplication rule

used when the probabilities of events are independent of each other, combined probability is the product of the events

used when you want to know the probability of one event occurring as opposed to another independent event

problem that involves more that one trait (9:3:3:1 ratio)

simple dominance

when the dominant allele's phenotype masks the presence of the recessive allele

incomplete dominance

one allele comes from each parent, but still goes through the principles of segregation and the law of independent assortment, but the phenotype mixes

alleles share equally in the expression of their phenotypes (both fully expressed). Ex: blood type

proteins produced on the surface of RBCs and determine blood type; protect from diseases

incompletely penetrant

when dominant alleles are present, but do not show up as phenotype

complete penetrance

every person having the allele shows the phenotype

the degree to which an allele expressed the phenotype differs from person to person; the variable strength of a trait

the normal phenotype

an alternative form of a normal gene that is not necessarily harmful

when genes hide or mask the action of other genes altogether. Ex: hair color

dominant epistasis

masks the presence of other alleles

when genes are so close together, they're inherited together (all or part of the time) - not all genes are subject to independent assortment

organisms with identical alleles may exhibit different phenotypes, due to differences in the chemical structure of DNA

genomic imprinting

the gender of the parent who contributes the allele affects how the trait is expressed

the strengthening of a trait as it is inherited

organisms with the ability to produce both viable sperm and eggs

organisms have wither functional male or female reproductive structures, not both

region near the kidneys where the embryo begins to develop, around the 4th week - 3 genes convert this tissue into organs that can become sex organs

bipotential gonads

genital ridge tissue present by the 7th week of development - can become testes or ovaries

the tips of chromosomes

sex determining region Y gene (SRY)

gene that makes men

every gamete that the individual produces has the same set of chromosomes (one each autosome and one X)

half of male gametes have one set of autosomes and an X and the other half have one set of autosomes and no sex chromosome

paired chromosome

single set of chromosomes

enzyme that is a key player in organisms with temperature dependent sex determination - converts testosterone into estrogen

one X chromosome is permanently and irreversibly turned off a female's body - only one X remains turned on

when females have an extra X chromosome, generally have a taller, thinner build

sex linked genes

genes located on sex chromosomes

sex limited traits

inherited in the normal autosomal fashion, but never expressed in one sex. Ex: female's producing milk, male birds with a bright color

the probability that an individual having a dominant allele will show its effects

sex influenced traits

the phenotype depends on the sex of the individual carrying the gene, coded by genes on autosomes. Ex: horns or hair

tight packing of DNA with histones

adenine, guanine, cytosine, thymine

adenine and guanine, compound composed of two rings

cytosine and thymine, compound composed of a single six-sided ring

ribose sugar that has lost one of its oxygen atoms, connects to base and phosphate to make a nucleotide

adenosine triphosphate

molecule used to power cells

oxygen atom is missing from the sugar molecule - defines D in DNA

phosphodiester bond

the bonds between a phosphate and 2 sugar molecules in a nucleotide strand

parallel and running in opposite directions

molecules that repel water

the conversion of light to chemical energy, occurs in chloroplasts in plant cells

rich in phosphorous and is acidic - original name of DNA

copying DNA accurately, quickly and efficiently; part of reproduction, development, and maintaining normal life

keeping something protected in its original state

semiconservative

only half of the molecule is conserved; the mode of replication

double stranded molecule that provides a pattern to copy

building blocks necessary to make DNA

consists of a sugar (deoxyribose), 1 of 4 nucleotide bases, and three phosphates

opens the double helix

prevents the helix from forming knots

lays down a short piece of RNA to get replication started

adds dNTPs to build the new strand of DNA

seals the gaps between the newly replicated pieces of DNA

replicates the ends of chromosomes

special proteins move along the double stranded template DNA until they encounter a group of bases in a specific order

leading strands

one bout of uninterrupted DNA synthesis

lagging strands

replicate in sections as new primers are laid down

the ends of chromosomes

theta replication

replication that refers to the shape of the chromosome taken on during the replication process

rolling circle replication

replication where double stranded template is broken at the origin to provide a free OH tail to start replication. Replication is continuous on one strand and lagging on the other

D-loop replication

replication like rolling circle replication, when a single strand is displaced and replication goes around the circle. the single strand is released and used as a template to synthesize a complementary strand

six copies of each chromosome. Ex: wheat

two copies of each chromosome. Ex: rice

protein that codes for the production of feathers and hair

gene containing

thousands of short sequences of DNA that are complementary to the part of the DNA to be sequenced

dNTPs (deoxyribonucleoside triphosphate)

one of the 4 nucleotide bases that lack and oxygen atom at the 3' spot

enzyme that puts the DNA molecule together

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