TTU Held BIOL 1402 Exam 2

Karyotpying

- a display if micrographs of the metaphase chromosomes of a cell arranged by size and centometer position; to determine of there's an abnormal number of chromosomes (due to non- disjunction)

a. if we brake open human cells in metaphase of mitosis, stain the chromosomes with dyes, take a picture with a microscope and arrange then in matching pairs

Pedigree Analysis

- To determine whether a gene is dominant/recessive and uses Mendel's concept of dominant and recessive alleles and his law of segregation. ; the X chromosomes vs. autosomal

Down Syndrome

Caused by an extra copy of chromosome 21 ("Trisomy 21"); characterized by heart and respiratory defects and varrining degrees of mental retardation.

Turner Syndrome

females lacking an X chromosome ; XO, O refers to the absence of the other X chromosome. They are short in stature and have webbing around the neck and shoulders but have normal intelligence. Have only 45 chromosomes but is NOT fatal. They are sterile

Klinefelter Syndrome

a male with an extra X chromosome (XXY or XXXY) that is sterile and has abnormally small teestes. Often has more feminine body characteristics. The abnormal sets with more than three chromosome( sex) are a result of disjunction.

Nondisjunction

an accident of meiosis or mitosis in which a pair of homologous chromosomes or pair of sister chromatids fails to separate at anaphase; causes down syndrome.

disjunction

the normal separation of chromosomes in meiosis or mitosis

Carrier

- Parents are heterozygotes for a recessively inherited disorder and who therefore does not show any symptoms of that disorder

Amniocentesis

- Genetic testing in the fetus

- Requires collection of fetal cells by inserting a needle through the abdomen into the uterus

- Cells are cultured to allow karyotyping to look for abnormalities

-Inform mother whether the child will have birth defect

Cystic Fibrosis

a genetic disease that occurs in people with two copies of a certain recessive allele characterized by an excessive secreation of mucus and concequent venerability; fatal if untreated

Achondroplasis

a form of human dwarfism caused by a single dominant allele

Huntingtions Disease

A human genetic disorder caused by a dominant allele, charaterized by uncontrollable body movements and degeneration of nervous system; usually fatal 10 to 20 years after the on set of symptoms

Alzheimers

a from of mental deteroration or dementia; characterized by confusion or memory loss

Chorionic Villi Sampling

- Doctor extracts sample of chorionic villus tissue from placenta

- Karyotyping results take only 24 hours and can be done earlier than amniocentesis

Aminocentesis

a genetic testing of the fetus to detect the presence of disease causing alleles in an individual genome. The test is done by extracting from the fetus with a needle

Heredity

Transmission of traits/features from one generation to the next.

In{her}itance of traits

Ultrasound

Uses waves to produce a picture of the fetus

Genetics

- Study of heredity

Parts of chromosomes and make of DNA

BLENDING THEORY

- Ancient theory of heredity

- Hereditary materials contributed by the male and female parents mix in forming the offspring (horse and donkey)

-irreversible and original colors are gone

Particulate Theory

- Traits are inherited like particles = genes

- Mendel's theory

-reversible and colors stay

Self-fertilization

In plants, sperm-carrying pollen lands on the egg-containing carpel of the same flower.

Cross-fertilization

- Fertilization of one plant by another plant.

- Mendel used this with pea plants to observe traits.

Pure-breeding strain

- Crosses between identical homozygotes

-same alleles

(ex. both parents are SS or ss)

Hybrid

The offspring of two different varieties.

HERETOZYGOUS- diff alleles (ex. Ss)

"P"

the parent individuals from which offspring are derived in studies of inheritance.

-parental generation

F1

The offspring of two (P) parental individuals F1 stands for the first filial. hybrid.

-Child generation

F2

F1 plants self-fertilize or fertilize each other giving an offspring F2 = second filial

-Grandchild generation

Allele

Diff/ alternate forms of gene (ex. long vs short S=dominant s=recessive)

Gene

Unit of inheritance, contains DNA. Consisting of a nucleotide sequence of a polypeptide

Dominant

Allele that determine's the appearance (represented by a capital letter)

Recessive

Allele that has no noticeable effect on the organism's appearance

- Only shows up if there are two (bb)

- Represented by lowercase letters

Locus

the particular site where a gene is found on a chromosome

Homozygous

Organism that has two identical alleles (ex. BB or bb)

Heterozygous

An organism that has two different alleles for one gene. (Bb)

Punnett Square

A diagram that shows the possible combinations of alleles that could occur when gametes combine (can show proportions of combinations). Studies the inheritance of random fertilization.

Allele Segregation

Law 1

A sperm or egg carries only one allele for each inherited characteristic because they combine at fertilization.

Independent Assortment

Law 2 Dihybrid

The inheritance of one characteristic has no impact of the inheritance of another (ex. you can have brown hair, but you don't have to have brown eyes)

-In meiosis the homologs pair but in mitosis they do not (shuffling of the deck)

Monohybrid Cross

Cross between two different homozygous organisms (ex. crossing PP purple plant with pp white plant)

3:1 (f2) of phenotypes of F2

3=dominant 1-recessive

Dihybrid Cross

Mating of parental varieties differing in two characters

(ex. RRYY with rryy) would produce all RrYy.

2 genes at a time (dom and rec)

9:3:3:1 (F2)

Testcross

Allows you to determine the genotype of an unknown parent

(Helps you tell if the unknown is heterozygous or homozygous)

3:1

The ratio of phenotypes in the F2 of a monohybrid cross (see p. 156)

9:3:3:1

The ratio of phenotypes in the F2 of a dihybrid cross.

Incomplete Dominance

- Heterozygote shows intermediate phenotype

- If the protein is a structure, the traits mix

- If it's an enzyme, the dominant trait shows, but it takes longer (pink rose)

Codominance

Heterozygote expresses both traits (alleles)

(ex. Blood type: A and B are dominant, creates AB)

Pleiotropy

One gene causes many traits

- "Go to many"

- Gene for albino causes white hair, pink iris, crossed eyes

-syndrome

Polygenic Trait

One trait is caused by many genes

- Quantitative traits (height, weight, etc.) are often this (ex. human skin color)

Epistasis

One gene masks or "dominates" a different gene, rather than an allele. (ex. the hair color of laborador retrievers)

Mosaicism

A trait of female mammals due to inactivation of one X chromosome in every cell.

- Solution of double proteins in XX is X-inactivation.

(calico cats - splotchy/patches of color)

Dosage Compensation

A trick for equalizing the "dose" of X genes in XX vs. YY individuals

Crossing Over=Genetic Recombination

Shuffling of genes on each chromosome (creates variety by shuffling genes)

Sex Chromosomes

The nonidentical pair of chromosomes

- Determine an individual's sex, and other functions (males have one X and one Y, females have two X)

Autosomes

The 22 pairs of chromosomes that are not sex chromosomes.

Criss-Cross Inheritance

How sex-linked (X-chromosome) genes are passed from Mom to son.

-Sons inherit their X from their mother

Mutant Allele

The less-occurring trait, not necessarily recessive. (weird traits)

Wild-Type Allele

Traits prevailing in nature (the more common traits)

- Not necessarily the dominant trait

Parental Phenotypes

Offspring looks like the parents

Recombinant Phenotypes

Offspring doesn't look like the parents (got recessive alleles).

DNA

- Double helix, bases are A,T,C,G, no oxygen (deoxyribose sugar), long, storage of genetic information.

-Information storage (eye color, hair color, nose shape)

RNA

Ribose sugar, bases are A,U,C,G, single stranded, short, messenger of genetic information.

Double Helix

- Bases point in and correspond to a base on the other strand

- Shape of DNA

A bind with T

G bind with C

Replication

- Conversion/copying of DNA into DNA (DNA acts as it own template)

- Steps are 1)Unwinding 2)Pairing 3)Joining

Transcription

- Conversion of information in one gene (DNA) into a messenger RNA (mRNA), (like burning a song onto a CD)

Translation

Process by which mRNA is decoded and a protein is produced

Unwinding

The two strands of DNA separate

Pairing

Free nucleotides in the DNA polymerase match up with the bases on the separated strands.

Joining

DNA ligase links the added bases together into a strand

DNA polymerase

Enzyme involved in DNA replication that joins individual nucleotides to produce a DNA molecule

Ribosome

Structure in the cell that has RNA and protein

Triplet Code

Three bases correspond with one amino acid

Codon

Combination of three "letters", nucleotides. ("word" of genetic code)

Anticodon

Three bases that would match up with a codon.

Genetic Code

The chart that matches codons with amino acids.

Redundancy of the Code

There are more possible combinations of codons than amino acids, so some repeat

mRNA

Encodes amino acid sequences and carries information into the cytoplasm

tRNA

Interprets codons into proteins

rRNA

This and proteins make ribosomes (most abundant kind of RNA)

Mutation

Change in sequence of nucleotides in DNA (creates heritable changes)

Mutagen

Causes mutations (source)

Sickle Cell Anemia

Caused by mutation

Missense Mutation

Base substitution which converts one amino acid into another

Nonsense Mutation

Converts an a.a. into a stop codon, causing a truncated protein.

Frameshift Mutation

Base insertion or deletion, which shifts the reading frame.

Complementary

For every rung, big and little bases will fit like jigsaw pieces

- A with T, C with G

Template

When DNA replicates and unwinds, it acts as its own __________

Operon

One unit of operation in regulation.

Operator

Section of DNA where the repressor binds

-non coding

("cow on DNA railroad tracks")

Promoter

- Made of DNA and non coding

- RNA Polymerase binds here

Repressor

Protein that binds operator and lactose

Structural Gene

DNA which codes for a protein

Inducer

Sugar molecule (lactose) which binds repressor protein

-binds repressor and changes its shape so it can't bind operator

Exon

Parts of a gene in RNA that are expressed, coding regions

Intron

Non coding regions of RNA

inserted of pieces of DNA (viruses like herpes)

Splicing

When introns are removed from RNA and exons are joined together

convert RNA into an mRNA

RFLP's

Technique of DNA fingerprinting

PCR

-before RFLP

- Amplify DNA (replication)

DNA Fingerprinting

uses RFLP's; the anylsis of DNA from samples of body tissue or fluilds, esspecialy when conducted in order to identify individuals

Homologies

Shared developmental origins (clitoris = penis)

(labia = scrotum)

Ovary

Where eggs are made.

Oviduct

The pipe the egg travels through.

Ovulation

The release of a mature ovum (egg) into oviduct.