Genetics Exam 1

Deoxyribonucleic acid

is the hereditary macromolecule in most life forms

RNA

plays a central role in the synthesis of proteins.

Biogenesis

the principle that all life forms come from reproduction by earlier life forms

Genome

refers to the genetic information needed to code for the biochemical processes and development of an individual

Chromosomes

are simply the structures that carry subsets of the genome of a species during cell division.

Linkage groupon

an abstract reference to the individual DNA content of each different kind of chromosome

DNA Replication

Makes DNA copies that are transmitted from cell to cell and from parent to offspring.

Transcription

produces an RNA copy of a gene.

mRNA

a temporary copy of a gene that contains information to make a polypeptide.

Translation

produces a polypeptide using the information in mRNA

Introns

are spliced out of the initial transcript leaving behind the coding sequences

DNA polymerases

are the enzymes that link nucleotides together to form a single strand

Promoter

a specific sequence of nucleotides upstream from the beginning of the gene’s coding region

Nucleosomes

Wrapping of histone proteins

Heterogeneous RNA

initial RNA transcript

Small nuclear ribonucleoproteins

These RNA plus protein complexes bind splice sites at the edges of an intron, cut the DNA, attach the adjacent exons, and remove the intron in the form of a lariat

Genetic Code

Translation dictionary

Shine

Dalgarno sequence

Chaperones

help produce the proper shape

point mutations

cause the substitution of one amino acid with another that differs in chemical properties and affects protein shape in a major way.

Sorting signals

are short amino acid sequences that are recognized by specific ultrastructural elements.

“one gene, one enzyme”

George Beadle and Edward Tatum

Cellular differentiation

is the gradual specialization of cells

Pattern formation

is the establishment of spatial organization of differentiated cells

Morphogenesis

the “origin of form.”

Apoptosis

Programmed death of cells

Transcription factors

which are regulatory proteins with at least two active sites

Repressors

inhibit transcription when they bind to DNA

Activators

increase the rate at which transcription occurs.

RNA polymerase I

transcribes rRNA in the nucleolus region of the nucleus

RNA polymerase II

transcribes mRNA throughout the genome.

RNA polymerase III

transcribes tRNA and some other types of small RNA.

Homodimer

is where the two factors are the same

Heterodimer

made up of two different transcription factors

Signal Transduction

an activated membrane receptor initiates a response pathway inside the cell

Secondary Messenger

A molecule that is produced intracellularly in response to signal transduction

Protein kinase

an enzyme that affects activity by adding a phosphate group to an amino acid of another protein.

G proteins

have the ability to bind guanine nucleotides.

cAMP

plays the role of an intracellular messenger in many pathways

Morphogenesis

is the process of shaping body form.

Gastrulation

a portion of the outer layer of the hollow blastocyst folds inward to produce a two

Homeotic mutations

have strange phenotypes in which the normal specification of one body part is altered into that of another

Hox complexes

a contraction of “homeobox.”

Segmentation genes

divide the body into a series of similar segments

homeotic genes

define the way in which each of the segment genes will develop.

Malformation

is a congenital anomaly in which the tissue is malformed, i.e., it did not form correctly from the start

Major malformations

are defined as those that have significant clinical implications and are not found in the general (normal) population

minor malformations

do not produce clinically significant problems and may occur in a small number of “normal” individuals

Agenesis

Lack of development

Hypogenesis

Underdeveloped

Heterotopia

Abnormal migration of cells

Ectopia

Abnormal migration of organ

Deformational changes

are the results of mechanical forces applied to otherwise normally developing structures

Disruption

Normally developing tissue may be subjected to insults that result in actual loss of cells and/or tissue. The resultant anomalies are due to the effects of the missing cells

Dysplasia

literally means “bad form.” that represents aberrant formation specifically at the level of the organization of cells into tissues

Syndromes

are patterns of congenital anomalies of more than one organ system with a common etiology.

Associations

to the known occurrence of certain anomalies that happen too often to be by chance, but without a defined etiology

Sequence

reproducible pattern of anomalies,multiple anomaly pattern

Dysmorphology

is the art and science of discerning recognizable patterns of congenital anomalies

Teratogens

are environmental agents that can cause birth defects if the mother is exposed to the agent during pregnancy

Structural gene

is often used to describe the nucleotide sequence that defines the amino acid composition of a protein

Regulatory sequences

site for the binding of regulatory proteins; the role of regulatory proteins is to influence the rate of transcription.

Promoter

site for RNA polymerase binding; signals the beginning of transcription

Terminator

signals the end of transcription

Ribosomal binding site

site for ribosome binding; translation begins near this site in the mRNA. In eukaryotes, the ribosome scans the mRNA for a start codon.

Start codon

specifies the first amino acid in a polypeptide sequence,

Stop codon

specifies the end of polypeptide synthesis.

MicroRNA (miRNA)

Fine tuning of gene expression

Ribosomal RNA (rRNA)

Recognition site of the translational complex

Transfer RNA (tRNA)

Shuttle of amnio acids to translational complex

Pseudogenes

gene ghosts

Minisatellites

form a class of tandemlyrepeated sequences that can vary from one location or one individual to another.variable number of tandem repeats (VNTRs).Each is between about 1 and 5 kb in length with repeated units of about a dozen to perhaps 100 nucleotides. variant regions of the genome consisting of repeats rich in guanine and cytosine (GC) that range from 10 to 100 bp.

Transposons

carry out transposition as DNA copies

Retrotransposons

spread after reverse transcription of an RNA molecule into DNA.

Microsatellites

are long repeats of two to six nucleotides

Nucleosome

a repeating unit composed of doublestranded DNA wrapped almost twice around a complex of histone proteins

chromatin remodeling

involves the partial or complete displacement of histones to allow access by transcription factors to promoter regions

Microsatellites

the smallest size of tandem repeats. They may also be referred to as short tandem repeats (STRs). In humans the size of the repeated unit is 2 to 6 bp, most commonly di

tRNA

its role in the transport of amino acids to the translational complex (RNA to protein)

Mitosis

to duplicate each chromosome and pass one copy of every chromosome into each of the two new nuclei of the diploid daughter cells.

Meiosis

is a reduction division involving two cycles

C Value

the amount of DNA in a haploid (1n) nucleus.

Centrosome

Contains a pair of centrioles is located in the cytoplasm near the nucleus.produce the array of microtubules that move chromosomes during nuclear division

Karyotype

is a picture of chromosomal makeup

Euploid

is the normal chromosomal makeup of an individual

Chromosome aberrations

changes in structure, occur when the linkage of genes within and between chromosomes is altered

Reciprocal translocation

involve the complementary exchange of segments between two nonhomologous chromosomes

Translocations

involve the movement of a piece of one chromosome to another.

Karyotype

is a conventional representation of chromosome structure and number

Aneuploid

means “not the correct multiple or number.”

Law of Segregation

Every individual possesses two alleles and only one allele is passed on to the offspring.

Law of Independent Assortment

the inheritance of one pair of genes is independent of inheritance of another pair.

Law of Dominance and Recessiveness

hybrid offspring will only inherit the dominant trait in the phenotype.

Heterozygous

individuals that carry different alleles

Homozygous

individuals that carry two same/identical alleles

Incomplete Dominance

affects the ways in which genotypes are expressed phenotypically

Autosomal Inheritance

Means that the gene is located on one of the autosomes.

Autosomal Dominant

Each affected person usually has an affected parent; occurs in every generation.

Autosomal Recessive

Both parents of an affected person are carriers; not typically seen in every generation

X linked Dominant

Females are more frequently affected because all daughters and no sons of an affected man will be infected; can have affected males and females in same generation if the mother is affected