Bio Exam studyguide (copy)

DNA stands for?

Deoxyribonucleic Acid

What does DNA coil around to make a chromosome?

Histones

What are the three parts of a nucleotide?

5-carbon sugar ,phosphate group and a nitrogenous base

What are some examples of nitrogenous bases?

adenine, cytosine, guanine and thymine)

Which two bonds are required to form DNA?

Phosphodiester bonds , Hydrogen bonds

What are Purines

Adenine and Guanine which consit of two rings with amine groups

Pyrimidines

Thymine and Cytosinem consist of one ring with amine groups. Thymine is a pyrimidine that is only found in DNA, while Uracil is only found in RNA

Chargaffs rule

A w/ T, G w/ C, A w/ U

1869, Swiss chemist identified nuclein in white blood cells?

Friedrich Miescher

Stole roslands franklins work, gave it to watson and kirk?

Maurice Wilkins

Stick and ball method

Watson and Kirk

supported the hypothesis that DNA replication was semiconservative meaning, one strand of DNA will be used to make another strand?

Matthew Meselson and Franklin Stahl

What needs to happen before a cell can divide?

Each DNA molecule needs to be copied

What connects DNA strands and which way do they go?

Carbon and anitparrael from each other

what cells are involved in meiosis

gamete cells

how many daughter cells are made in meiosis

4 genetically different cells

how many cells do you get per parent

23 cells

oocytes

premature cells females are born with

spermatocytes

premature cells males are born with

homologous chromosomes

Paired chromatin that are identical

diploid cells

two complete sets of chromosomes, one from each parent

haploid cells

half the number of chromatin than what was in the original cell

genes

sections of DNA that code for a trait

crossing over

exchange of genes during sexual reproduction between two homologous non-sister chromatids that results in recombinant chromosomes

Prophase 1

centrioles release spindle fibers, nucleus disappears, chromatin turns into chromatid, pairs up with another sister chromatid=tetrad

synapsis/ crossing over

chromatid from each pair will link parts of their “arms” in order to exchange sequences of nucleotides or genes

synapsis

point where “arms bond”

Prophase I

Centrioles begin to release spindle fibers and move to opposite poles. The nucleus disappears. Chromatin condense into chromatids

Metaphase 1

tetrad lined up and formed, spindle fibers reach out and attach to the kinetochores of the tetrads

Prophase I picture

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Metaphase 1 picture

Anaphase I picture

Telophase I picture

Cytokinesis I picture

Prophase II picture

Metaphase II picture

Anaphase II picture

Telophase II picture

Cytokinesis II picture

Anaphase I, Telophase I & Cytokinesis I

Spindle fibers will shorten, sister chromatids not identical anymore (pulled to opposite sides)

Prophase II

identified by the two cells, nucleus disappears and sister chromatid

Metaphase II

Spindle fibers connect to the kinetochores of sister chromatids

Anaphase II

46 chromatids were separated and pulled to opposite pole There should be 23 chromatids being pulled to each side in both cells

Telophase II

cleavage furrow will begin to form in both cells, 2 nuclei will reform, and chromatids will begin to de-condense into chromatin “in separate cells”

Cytokinesis II

4 Genetically different sperm or egg cells, with 23 chromatin each

Gregor Mendel

“Father of Genetics”

a priest who studied pea plants to learn about traits

he studied pea plants because they have many traits and only exist in two forms – tall or short

traits

a characteristic that an organism can pass on to its offspring through its genes

heredity

passing of traits from parents to an offspring

genetics

the study of heredity

gene

a segment of DNA on a chromosome that codes for a specific trait

alleles

the different forms of a gene

recessive allele

an allele that is masked (covered up) when a dominant allele is present; represented by a lowercase letter

dominant allele

an allele whose trait always shows up in an organism when the allele is present; represented by an uppercase letter

genotype

an organism’s genetic makeup, or allele combination (ex. BB, Bb, bb)

homozygous/purebred

having identical alleles for a trait (ex. BB or bb)

heterozygous/hybrid

having different alleles for a trait (ex. Bb)

phenotype

the trait that is being expressed can be seen or not seen

incomplete dominance

Instead of looking like the dominant trait when heterozygous the offspring happen to have a third, different trait.  Often it appears to be a combination or __**“blend”**__ of the dominant and recessive trait.

codominance

Type of inheritance that includes 2 dominant traits, no recessives.  One dominant cannot “win” over the other so instead you __**“see”**__ both traits

insertion

adding a nucleotide

deletion

deleting a nucleotide=frameshift

subsitution

a nucleotide is swapped for a different nucleotide

sex linked chromosomes

Sex-linked inheritance is when the trait is carried by one of the sex chromosomes (X or Y).  We will only be examining X-linked inheritance, no Y traits.  This means the allele will only be present on the X.

silent mutation

switched for same amino acid, so no change noticed

missense mutation

switched for different amino acid

nonsense mutation

early stop

long arm of a chromosome

q arm

short arm of a chromosome

p arm

how is deletion caused

piece of chromosome is lost

how is inversion caused

Chromosome segment breaks off, Segment flips around backwards, segment reattaches

how is duplication caused

Occurs when a gene sequence is repeated

how is translocation caused

a piece breaks off and is attached to another chromosome

mononmy

a person is missing or has an dxtra chromosome

nondisjunction

Failure of chromosomes to separate during meiosis

Cri-Du-Chat

Deletion of part of the 5th chromosome

46, XX or XY, del(5)

Mosaic Trisomy 16

47, XX or XY, +16

An extra copy of chromosome 16 is in *some* of the cells, while the other cells are normal

Typically born early and with a low birth weight, many grow to a normal weight and height by toddler age

Patau syndrome or Trisomy 13

Extra copy of chromosome 13

47, XX or XY, +13

May also have cleft palate and weak muscle tone

Full Trisomy 16

47, XX or XY, +16

An extra copy of chromosome 16 in all of cells

Most common reason for miscarriage

Trisomy 18 or Edward Syndrome

An extra copy of chromosome 18

47, XX or XY, +18

Clenched hands, rounded

feet, unusual shaped chest,

Limited Intellectual disabilities

Down Syndrome or Trisomy 21

An extra copy of chromosome 21

47, XX or XY, +21

Philadelphia Chromosome

Chronic Leukemia

A translocation of part of #9 and #22

46, XX or XY, t(9,22)

uncommon type of cancer of the bone marrow where blood cells are made

Klinefelter Syndrome

An extra X chromosome

47, XXY, +23

Can cause sterility, smaller testes, extra pectoral tissue (gynecomastia), can have learning and social delays

Less than average amounts of testosterone

XYY Syndrome or Jacob Syndrome

An extra Y chromosome

47, XYY, +23

Often tall and thin, with possible learning delays/disabilities

XXX (Trisomy X)

47, XXX, +23

Extra X chromosome, for a total of XXX instead of XX

Normal physically but weak muscle tone

Tall stature, learning delays, limited fertility

Turner’s Syndrome (Monosomy X)

Missing an X0 chromosome

45, X0, -23

Female, sterile, short stature, webbed neck, puffiness of skin, kidney and heart defects.

Prokaryotes

Single celled

have cell walls made of peptidoglycan

have ribosomes, cytoplasm, cell membrane and a singular, circular DNA that floats in a nucleoid region and some can have a plasmid

how do prokaryotes reproduce

asexually; by binary fission, not mitosis/meiosis

step one of binary fission

No interphase

step two of binary fission

Single circular DNA is replicated

step three of binary fission

Cell elongates

step four of binary fission

The cell membrane pinches and a septum (like a cell plate) is formed

step five of binary fission

The cells separate creating a single-cell with a cell wall, cell membrane, DNA

after a cell goes through binary fission what happens

go through gene expression/read the code of the DNA, convert into mRNA to make proteins (enzymes, protein channels, protein pumps etc.) in the cytoplasm

operon

group of genes that are transcribed at the same time by RNA polymerase to create a strand of mRNA that will code for a protein

Lac Operon

codes (has the instructions) for the lactase enzyme, needed to breakdown lactose into glucose

Trp Operon

codes for the amino acid tryptophan, needed by bacteria to make certain proteins

repressed

turned off

induced

turned on

bacterial conjugation

bacteria have the ability to “share” their genetic information

use of bacterial conjugation

bacterial cell has plasmid that contains a gene for antibiotic resistance, and let’s say the gene makes the bacterial cell resistant to penicillin.