Biology Exam 3 set #2

Chromosome

threadlike structure within the nucleus containing the genetic information that is passed from one generation of cells to the next.

G1 Phase

1st gap phase of cell cycle (longest).

S Phase

synthesis of DNA, the genetic material.

G2 Phase

2nd gap phase.

M Phase

mitosis and cytokinesis (shortest phase).

Mitosis

in eukaryotic cells, a process of cell division that forms two new nuclei, each of which has the same number of chromosomes.

Chromatid

one of two identical strands into which a chromosome splits longitudinally.

Sister Chromatids

two duplicated chromatids that are still joined to each other after DNA replication.

Kinetochore

group of proteins that bind to a centromere and are necessary for sorting each chromosome.

Centromere

region of tightly associated 2 sister chromatids; attachment site for kinetochore proteins.

Centrosome

structure present in the cytoplasm of animal cells, important during cell division; functions as a microtubule-organizing center. A centrosome has two centrioles.

Centriole

in animal cells, a cytoplasmic organelle that organizes the mitotic spindle fibers during cell reproductions.

Microtubules

hollow protein filament composed of tubulin proteins that are part of the cytoskeleton and are important for cell shape, organization, and movement.

Mitotic Spindle

an assemblage of microtubules and associated proteins that is involved in the movements of chromosomes during mitosis.

Interphase

chromosomes have already replicated.

Prophase

sister chromatids condense, and the mitotic spindle starts to form. Nuclear envelope begins to dissociate into vesicles.

Prometaphase

nuclear envelope has completely dissociated into vesicles, mitotic spindle fully formed. Sister chromatids attach to spindle via kinetochore microtubules.

Metaphase

sister chromatids align at metaphase plate.

Anaphase

sister chromatids separate, and individual chromosomes move toward the poles as kinetochore microtubules shorten. Polar microtubules lengthen and push the poles apart.

Telophase

chromosomes condense, and the nuclear envelope reforms. Cytokinesis separates the mother cell into 2 daughter cells, through a cleavage furrow in animal cells. In plants, a cell plate forms a wall between the daughter cells.

Metaphase Plate

an imaginary plane midway between the two poles of a cell in metaphase on which the centromeres of all the duplicated chromosomes are located.

Cleavage Furrow

(animal cells) area that constricts like a drawstring to separate the cells during cytokinesis.

Cytokinesis

division of cytoplasm to produce 2 distinct daughter cells.

Cell Plate

disk containing cell wall material that develops in plant cells during cytokinesis, eventually dividing the cell into two daughter cells.

Meiosis

(genetics) cell division that produces reproductive cells in sexually reproducing organisms.

Synapsis

the process of forming a bivalent (unique to meiosis).

Crossing Over

exchange of genetic material between homologous chromosomes during meiosis; allows for increased variation in the genetic info. that each parent may pass to offspring.

Recombination

the formation of new combinations of the different alleles of each gene on a chromosome; the result of crossing over.

Segregation (Mendel's Law)

separated chromosomes during meiosis.

Independent Assortment (Mendel's Law)

when two or more characteristics are inherited, individual hereditary factors assort independently during gamete production, giving different traits an equal opportunity of occurring together.

Bivalent

homologous pairs of sister chromatids associated with each other, lying side by side.

Homologs

same as homologous chromosomes; chromosomes with identical sets of genes or loci.

Chiasma, Chiasmata

connection at a crossover sight of two chromosomes.

Homologous Chromosomes

pair of chromosomes having the same gene sequences, each derived from one parent.

Prophase I

homologous chromosomes synapse to form bivalents, and crossing over occurs. chromosomes condense, and the nuclear envelope begins to dissociate into vesicles.

Prometaphase I

nuclear envelope completely dissociates into vesicles, and bivalents become attached to kinetochore microtubules.

Metaphase I

bivalents randomly align along the metaphase plate.

Anaphase I

homologous chromosomes separate and move towards opposite poles.

Telophase I

chromosomes decondense, and the nuclear envelope reforms. The 2 daughter cells are separated by a cleavage furrow.

Prophase II

sister chromatids condense, spindle starts to form. Nuclear envelope begins to dissociate into vesicles.

Prometaphase II

nuclear envelope completely dissociates into vesicles. Sister chromatids attach to spindle via kinetochore microtubules.

Metaphase II

sister chromatids align along the metaphase plate.

Anaphase II

sister chromatids separate, and individual chromosomes move towards poles as kinetochore microtubules shorten. Polar microtubules lengthen and push poles apart.

Telophase II

chromosomes decondense, and the nuclear envelope reforms. Cleavage furrows separate the 2 cells into 4.

Alternation of Generations

a life cycle in which there is both a multicellular diploid form, the sporophyte, and a multicellular haploid form, the gametophyte; characteristic of plants and some algae.

Bacterial Conjugation

type of genetic transfer between bacteria that involves a direct physical interaction between 2 bacterial cells.

During the cell cycle DNA is replicated in \______.

s phase

which of the following is not a type of rna?
-small nuclear
-peptide
-messenger
-transfer
-ribosomal

peptide

the genetic code is \_____, but not \____.

redundant and ambiguous

Which carbon is the phosphate group attached to in a nucleotide?

5'

Which scientist helped establish the one gene one peptide dogma?

Beadle and tatum

Which scientist played a critical role in discovering the molecular structure of dna?

rosalind franklin

which scientist provided evidence tht dna is replicated semi conservatively?

meselson and stahl

which scientist used isomers of sulfer and phosphate to label bacteriophage. Labeling provided strong evidence that dna is the molecule of inheritance.

hershey and chase

during elongation of translation where do tRNA's carrying amino acids dock or land?

a-site

ten percent of the bases in a sample of dna extracted from a eukaryote are Adenine. What percentage of cytosine is found in this dna sample?

40%

what is a fertilized egg called?

zygote

what enzyme catalyzes the attachment of amino acids to tRA molecules?

aminoacyl-tRNA synthase

production of a protein is called-

translation

where would one expect to find the longest telomers?

skin cells from a 2 year old

ensures the unambiguous condition of genetic code-

aminoacyl-tRNA synthase

adds rna to the start of a growing dna daughter strand

primase

unwinds the alpha helix at the replication fork

helicase

involved in removing introns

spliceosome

which of the following is a purine?
-thymine
-adenine
-arginine
-serine

adenine

transcription\=?

produces all types of rna adding the 5' end of one nucleotide to the 3' end of the next nucleotide

t/f: mitosis can occur in a haploid or a diploid cell.

true

used by avery and macloud to digest a nucleic acid-

dnase

this protein is very accurate making a mistake 1/10,000 events-

dna polymerase

catalyzes the reaction that binds dna pieces back together-

ligase

how many nucleotides in a codon?

3

how many anticodons are there?

61

the process by which haploid cells are produced by diploid cells is called-

meiosis

the basic unit of heredity is called a-

gene

a pregnancy test is based on the detection of \______ in the urine of the woman

chorionic gonadotroponin

which hormone is most responsible for ovulation?

luteinizing hormone

which of the following regulate sperm production and nourish the developing sperm?

sertoli cells

which of the following hormones stimulates the production of testosterone in men?

luteininizing hormone

it contains enzymes used to dissolve the protective layers around the egg-

acrosome

once sperm are made, where are they stored?

epididymis

in the female one hormone increases following ovulation and stays high until menstruation begins. what hormone?

progestone

both alleles of a gene are fully expressed. what name is given to this genetic phenomenon?

co-dominance

what phase of meiosis do homologous chromosomes separate in?

anaphase 1

at the end of meiosis 1:

cells are haploid

a cell has 9 pairs of chromosomes. Following mitosis how many chromosomes will be in each cell?

18

an cell has 3 pairs of chromosomes. Following meiosis 1 and 2 how many chromosomes will be in each cell?

3

which type of chromatin is metabolically active (can be transcribed)?

euchromatin

what phase of meiosis does crossover occur in?

prophase 1

intervening sequences that are transcribed, but not translated into proteins are called-

introns

during the g1 phase of the cell cycle the dna and histone-protein molecules should be called \______.

chromatin

What 4 nucleotide bases compose DNA?

Adenine, Thymine, Cytosine, Guanine

How does DNA bond? (what nucleotides go with what)

Adenine goes with Thymine, Cytosine goes with Guanine.

What do Covalent bonds form in DNA?

The "Rails" of the DNA Ladder

What do Hydrogen bonds form in DNA?

The "Rungs" of the DNA Ladder.

What makes DNA so stable?

Millions of Hydrogen bonds

What 3 things are the DNA double helix composed of?

1. "rails" that are strands of sequences of DNA, for that gene.

2. the 5' to 3' strand (its direction)(AAGCT)

3. the 3' to 5' strand (it's compliment)(TTCGA)

Is DNA replication conservative or no? Why?

It is semi-conservative. Each original strand (parent) becomes a template and a new strand (daughter) is built off of each template.

What must you do in order for a DNA strand to be used as a template?

Separate (denature) it.

What do helicase enzymes do?

Break down the Hydrogen Bonds between the strands.

What happens after the Helicase enzymes unwide the strands? What goes on during this process?

DNA ligases begin building the new copy strand. The ligases bond the bases of the new strand together. During the process, "mistakes" can happen called "mutations" when nucleotide is put where it does not belong.