GN301 Exam 1 Material

AHHHHHHHHHHHHHH genes and things boooooo

public health programs goal

to help assure conditions are present so people can be healthy

marfan syndrome

dominant disorder; heart valve defects, aortic aneurysms and longer limbs

allele

form of a gene

carrier

has one allele for a recessive disorder, meaning they do not exhibit it but can pass it down

karyotype

organized array of cell’s chromosomes

gene therapy

insertion of new genes into a cell to correct an error or treat a disorder

genetic counseling

assist people in understanding genetic diseases and how to manage them; nondirective, so the patient can make their own decisions

Huntington’s disease

degenerative dominant neurological disorder results in death 15-18yrs onset

Sickle Cell Anemia

recessive; affects hemoglobin making red blood cells abnormally shaped; this restricts blood flow and does not carry oxygen well

Cystic Fibrosis

recessive; thick mucus in lungs leading to respiratory infections and breathing difficulties; chromosome 7

Osteogenesis imperfecta

dominant mutation; decreased mobility and bone fractures

Xeroderma Pigmentosum

recessive; no repair mechanism against UV radiation; allergic to sun

autosomes

pairs 1-22; non gamete chromosomes

mutation

change in the DNA sequence; source of genetic variation

How do genetics and public health intersect?

use genetic technology to prevent disease; prenatal diagnosis and embryo selection; use of genetic info and DNA databases

ethical issues with genetics

where do we stop? what laws should or shouldn’t protect us? can we reject people due to genetic disorders?

nucleus

contains genetic material; surrounded by nuclear membrane

mitochondria

contain circular DNA molecule passed from mother to children; breaks down nutrients o mke energy

ribosomes

site of protein synthesis

endoplasmic reticulum

rough er: ribosomes and protein folding

smooth er: lipid synthesis

golgi apparatus

starch production and lipid storage

plasma membrane

made of phospholipid bilayer with channels that allow controlled molecules to pass

lysosomes

break down bacteria, debris and excess nutrients

Leber’s Disease

mutation in mitochondria; lost sight

Long Q-T Syndrome

faulty potassium channel; abnormal heart rhythm

Cystic Fibrosis

defective chloride channels

chromosome

15 DNA, 10 RNA, 75 protein; have a centromere, telomeres and >1 origin of replication

chromosome positions

kinetochore

protein structure surrounding the centromere

Somatic Cell Cycle

G1 (Gap 1): one chromatid

S (Synthesis of DNA)

G2 (Gap 2): prepare for cell division: 2 chromatid

Mitosis: cell division of identical cells: 2 chromosomes

interphase

G1+S+G2

who determined there were 46 chromosomes?

Tjio and Levan

what do homologous chromosomes have in common?

same length, same centromere, position, same banding pattern, and same genetic loci

FISH (Fluorescent in situ Hybridization)

allows us to examine the telomeres which provide stability for the ends of chromosomes

Steps of Mitosis

interphase: chromosomes are long and thin

prophase: coil up and spread through volume of cell; chromosomes move toward center cell

metaphase: chromosomes align in the middle; spindle fibers connect to kinetochores

anaphase: centromeres divide; spindle fibers pull to opposite poles

telophase: nuclear membrane forms enclosing chromosomes in nucleus

Steps of Meiosis I

Prophase I: chromosomes condense and synapse

Metaphase I: align on metaphase plate

Anaphase I: homologous centromeres pull apart the synaptonemal complex

Telophase I: nuclear membrane reforms, chromosomes unwind and elongate

Meiosis II

Prophase II: two distinct cells each with 2 chromosomes which coil up again

metaphase II: chromosomes align on equator

anaphase II: centromeres divide and pulled away

telophase II: nuclear membrane reforms; all 4 cells have two chromosomes with one chromatid

meiosis variation techniques

shuffling of maternal and paternal chromosomes; crossing over

when does crossing over occur

prophase I of meiosis

reductional division (I)

number of chromosomes in daughter cells is half the number in the original cell; separation of homologous chromosomes

equational division (II)

number of chromosomes at the beginning and end of the cycle is the same, but daughter cells only have one chromatid; separation of chromatids

recombination

homologous chromosomes exchange arms

synapse

homologues pair up and form a synaptonemal complex; zip together

Goals of Meiosis

\-produce gametes with a haploid number of chromosomes

\-provide variability from generation to generation

cell types in oogenesis

\-discontinuous process; in fallopian tubes

\-oogonium: diploid and divides

\-primary oocyte: diploid and divides unevenly

\-secondary oocyte: haploid; has the most cytoplasm

\-ovum: haploid; s. oocyte divides and develops one half

cell types in spermatogenesis

\-occurs in seminiferous tubules

\-spermatogonium: diploid, undifferentiated precursor cells

\-primary spermatocyte: diploid, about to start meiosis

\-secondary spermatocyte: haploid; p. divided

\-spermatid: haploid that mature into sperm

\-sperm: mature gamete cell

nondisjunction

mistakes in separation of chromosomes in meiosis; occurs in anaphase

polar body

the weaker, uncomplete cell from meiotic division of oocyte

mutations are likely in

sperm

abnormal chromosome likely in

eggs

barriers sperm face getting to the egg

corona radiata: follicle cells

zona pellucida: glycoprotein layer

Relate the timing of ovulation, the second meiotic division, fertilization and syngamy: What is the correct order?

ovulation→ fertilization → syngamy → meiotic division

About how long after fertilization does implantation occur? Where does implantation occur?

occurs at the embryo stage, week or so after fertilization

Whose cells (mother’s or baby’s) are use to make the following structures: placenta, umbilical cord, chorion, amnion?

placenta: both

umbilical chord: embryo

chorion: embryo

amnion: embryo

syngamy

nuclei of egg and sperm fuse to form zygote

acrosome

coat of enzymes that help sperm penetrate the egg

CVS

Chorionic Villus Sampling; catheter is inserted through vagina to collect chorionic villi

amniocentesis

needle sent through abdomen and into the womb to retrieve amniotic fluid

cell-free fetal testing

maternal blood screening test

Why IVF?

couples cannot conceive naturally; desire preimplantation diagnosis

guidelines for IVF

no multifetal pregnancy reduction, no more than about three births; usually entails 1-2 maybe three embryos

Gregor Mendel

Friedrich Miescher

isolated DNA from white blood cells and called it nuclein

Boveri and Sutton

Theory of Inheritance; recognized chromosome inheritance patterns

Avery, McCarty and Macleod

proved DNA is genetic material

Watson and Crick

established the structure of DNA

Franklin and Wilkins

X-ray diffraction; took a famous picture of DNA

Chargaff

conducted base composition studies

structure of DNA

base is connected to the 1’ carbon of the sugar and phosphate is connected to the 5’ carbon of sugar; 3’ end of the first nucleotide is joined with the 5’ of the next

Structure of RNA

has an OH attached to the 2’ carbon rather than just an H

complementary base pair

AT uses 2 H bonds, CG uses 3

hydrophobic interactions

main force of joining two strands of DNA

plectonic coil

strands must be unwound to separate

purine bases

adenine, guanine

pyrimidine bases

thymine, cytosine, uracil

chromatin

complex of DNA, chromosomal proteins and RNA within nucleus

histones

proteins that DNA wrap around to form chromatin

conservative replication

original double stranded is maintained and produces a whole new one

dispersive replication

both daughter molecules would have some new and original parts

Meselson and Stahl

sampled DNA in N15 and N14 and used a density gradient centrifugation to identify how DNA replicates

semi-conservative replication

the two original strands would separate gain a new complementary strand

what enzyme adds on nucleotides to growing strand during replication

DNA polymerase

enzyme assists in replicating the ends of eukaryotic chromosomes?

telomerase

leading

continuous replication; bottom to top: 5’ to 3’

lagging strand

discontinuous replication; replication cannot happen the same way it is unwinding meaning, it must unwind a bit and start from the top and go down, done in fragments

okazaki fragment importance

the 5’ to 3’ fragments made in the lagging strand

phosphodiester bonds

bonds use to join base pairs to the existing chain

DNA is produced…

5’ to 3’

RNA primer importance

required as a starting block for the DNA polymerase

mRNA

messenger RNA; carries coded information from DNA to cytoplasm

tRNA

transfer RNA; carries amino acid to ribosome and position them for assemble into protein

rRNA

ribosomal RNA; component of ribosomes (site of protein synthesis)

template strand

only one DNA strand is transcribed, the template strand; RNA is antiparallel and complementary to it

nontemplate strand

coding strand, not transcribed

translation occurs where

in the cytoplasm

primary transcript to mature mRNA

capping → tailing (PolyA tail) → removal of introns and joining exons

promoter

sequence of DNA that contains regions of regulation for transcription

exon

parts that code for protein

intron

intervening sequences that need to be removed

snRNA

small nuclear RNAs; complex with proteins to assist in splicing