Biology Lab exam #3

Cytokinesis

division of the cytoplasm to form two separate daughter cells

parent cell

original cell before cell division

daughter cells

the two new cells that result from mitosis and cytokinesis

cell cycle

the sequence of growth, DNA replication, growth, and cell division that all cells go through.

Interphase

the longest part of thr cell cycle. 90% of cell cycle. 3 sub-phases: G1, S, and G2.

G1 phase

cell increases in size and builds up energy reserves.

S phase

DNA replication

G2 phase

second phase of growth and energy acquisition.

M phase

active cell division. 10% of cell cycle

G0

mature non-dividing cells are in this phase. like nerve cells after maturity.

Mitosis

cell division, occurring in nucleotide cells that results in daughter cells with identical chromosomes and organelles to the parent cell. responsible for the growth abd maintenance of tissues associated with all life processes except sexual reproduction. 5 stages: prophase, prometaphase, metaphase, anaphase, and telophase.

Prophase

the chromosomes condense and become more tightly coiled. they appear as teo sister chromatids bond together at the centromere. the cytoskeleton disassembles and the mitotic spindle begins to form. the nuclear envelope begins to break down.

Centromere

the central region where the two chromatids are bound together.

mitotic spindle

composed of the centrosomes and extending microtubules.

Prometaphase

the nuclear envelope fragments and the microtubules surrounding the spindle enter the nuclear area and interact with, and attach to the attached chromosomes. the chromosomes begin to move toward the cells equator.

Metaphase

all of the chromosomes become aligned at the metaphase plate and the centrosomes move to opposite poled of the cell, on either end of the mitotic spindle. longest of the mitotic phases.

Anaphase

cromatids are pulled apart creating daughter chromosomes. chromosomes move to opposite poles via spindle fibers, with the centromere leading the way. The spindles move apart from one another and the cell begins to elongate. as anaphase progresses, the chromosomes are pulled farther apart. it is the shortest stage.

Telophase

nuclear envelopes are formed around each around each of the newly separated sets of chromosomes. the chromosomes assembled at the poles of the cell become less condensed. nucleus is now divided into two identical nuclei.

Cytokinesis in animal cells

cleavage furrow forms and cell pinches in two

cytokinesis in plant cells

cell plate forms

Meiosis

A two-stage type of cell division in sexually reproducing organisms that results in 4 genetically distinct daughter cells with half the chromosome number of the original cell. Produces gametes (eggs and sperm).

Prophase I (Meiosis)

the chromosomes condense and the microtubule spindle forms. the homologous chromosomes pair up by size and theb become closely associated and entwined around one another during synapsis. crossing over then occurs. the chromosomes cross over one another exchanging genetic information and forming crisscrossed regions called chiasmata. the movement of centrosomes, the dispersal of nuclei, ans the breakdown of the nuclear envelope. requires 90% of time required for meiosis.

chiasmata

holds the two homologous chromosomes together through anaphase I.

Metaphase I (Meiosis)

Pairs of homologous chromosomes move to the equator of the cell. the chromatids in each chromosome attach to the kinetochore microtubules, directing one chromosome from each pair toward opposite poles.

Anaphase I (Meiosis)

Homologous chromosomes separate into sister chromatids. and each moves toward an opposite pole. Microtubules begin to shorten.

Telophase I (Meiosis)

the separated sister chromatids form a cluster at each pole of thr cells. forms 2 daughter cells with half the number of chromosomes as the parent cell.

Prophase II

a new spindlebapparatus is formed in each cell and the nuclear envelope breaks down.

Metaphase II

the chromosomes made of non-identical sister chromatids are positioned along the metaphase plate. the kinetochore microtubules attach to each of the chromatids.

Anaphase II

the sister chromatids separate from one another as the centromeres separate, and move to opposite poles of the cell.

Telophase II

the nuclei form and the chromosomes begin to decondense.

describe the process of the mitotic spindle and microtubules in mitosis.

In prophase, the mitotic spindle begins to form. It is composed of microtubules and is formed by centrosomes. In prometaphase. the microtubules enter the nuclear area and attach to the condensed chromosomes at the kinetichores. the chromosomes that are attached to the microtubules are theb moved toward the middle of the mitotic spindle. In metaphase, all of the chromosomes line up in the middle of the spindle and become aligned at the metaphse plate. Then in anaphase, the kinetochore microtubules shrink, and the daughter chromosomes are moved to opposite poles of the cell. the spindles also move apart from each other, elongation the cell.

Are the chromosomes in mitosis and meiosis a mixture of mother and father chromosomes?

the chromosomes in mitosis are a mixture of mother and father chromosomes. Half of the chromosomes come from you father and half come from your mother. in humans there are 23 pairs of chromosomes, one set from your mother and one from you father making 46 chromosomes total. During prophase I of meiosis there is an exchange of parts of chromosomes between parental and maternal homologs at the chiasmata (called crossing over), leading to chromatids that have both paternal and maternal segments.

G2 of interphase picture plant

start codon

AUG (methionine) the first amino acid that signals the start of protein synthesis.

Prophase (picture) plant

Prometaphase plant picture

Metaphase plant picture

Anaphase plant picture

G2 of Interphase (Mitosis) animal picture

prophase in animal cell picture

prometaphase in animal cell picture

telophase plant picture

Recombinant DNA

DNA that has been manipulated by researchers so that one or more nucleotides have been inserted, changed, or deleted.

telophase animal cell picture

PCR (polymerase chain reaction)

A laboratory technique for amplifying and synthesizing DNA from an existing template.

Primers

short oligonucleotides (strands of nucleotides) ranging from 18 to 45 bases in length.

Metaphase picture animal cell

anaphase animal cell picture

Denaturation

the DNA is heated to separate the two DNA strands from one another.

describe the similarities and differences between prophase I and prophase II.

In prophase I and Ii the spindle apparatus forms ans the nuclear envelope breaks down. in prophase I the homologous chromosomes pair up in synapsis and the cross over one another, exchanging genetic information and forming regions called chiasmata. this does not occur in prophase Ii. In prophase Ii. there are non-identical sister chromatids and no synapsis or crossing over occurs.

Genetics

the science of heredity, or how specific characteristics (genes) are passed from generation to generation.

Heredity

the distribution of features from one generation to the next. these features are called traits and are expressed in physical characteristics such as eye color, hair thickness. and height.

Chrimosomes

carry genes and are found in the nucleus. each chromosome contains one DNA molecule.

units of heredity

genes

human genetics

the scientific study of heredity as it relates to humans

Genotype

genetic makeup of an organism

Phenotype

An organism's physical appearance, or visible traits.

Alleles

Different forms of a gene

Diploid

2 sets of chromosomes, one from their mother and one from their father.

homologous pairs

pairs that contain the same types of genes

Annealing

the DNA is cooled which allows the primers to bind to the target DNA.

extension

the new DNA is synthesized with the help of DNA polymerase and deoxynucleotide triphosphates (dNTPs).

DNA polymerase

an enzyme that catalyzes the synthesis of the DNA along the template strand, starting at the 5x end and continuing to the 3' end. adds to 3' end.

Deoxynucleoside triphosphate (dNTP)

individual units of 4 nucleic bases (A, T, G, C) which help to build the new DNA.

Amplification

occurs in cycles. each cycle exponentially increases the number of newly synthesized DNA strands. a cycle consists of repeating the steps of denaturation, annealing. and extension.

the ___ step of PCR results in primers binding to the target DNA.

annealing

gel electrophoresis

a technique by which molecules are separated by size and electrical charge as a result of traveling through a block of agarode gel by means of an electric field.

what charge does DNA have?

negative. DNA travels from the cathode (negatively charged electrode) through the agarose gel to the anode (positively charged electrode)

the larger the molecule, the ___ it travels through the agarose gel.

slower

a catalyst enzyme that extends DNA strands

DNA polymerase

molecular biologists investigate the manipulation of ___ to understand the interactions between the various systems of a cell.

DNA, RNA, and protein synthesis

what creates the genetic code?

the order in which the four DNA nucleotides are arranged.

Recombant DNA has been manipulated so that one or more nucleotides have been ___.

changed, deleted , and inserted.

gel electrophoresis is used to separate DNA molecules by ___

size

true or false? both DNA and food dyes are negatively charged and move towards the positive pole during electrophoresis.

true

dominant allele

An allele whose trait always shows up in the organism when the allele is present.

recessive allele

An allele that is masked when a dominant allele is present

incomplete dominance

Situation in which one allele is not completely dominant over another allele. Example: red flower and white flower makes a pink flower.

sex-linked traits

Traits controlled by genes located on sex chromosomes. only present on the X or Y chromosome

hemizygous

A gene present on the X chromosome that is expressed in males whether it is recessive or dominant.

monohybrid cross

A cross between individuals that involves one pair of contrasting traits

dihybrid cross

Cross or mating between organisms involving two pairs of contrasting traits. punnet square in which 2 genes or traits of interest are examined at one time.

pedigree chart

family trees that show phenotypic patterns

Autosomal

all the other genes in the body that are not sex-linked.

cystic fibrosis

caused by a single recessive allele in the seventh chromosome. Thickened mucus in the lungs, liver, and digestive organs; death in early adulthood unless symptoms are treated

Tay-Sachs disease

recessive, lipids accumulate in brain cells, deterioration of nerve cells; mental and physical disabilities; death during childhood

sickle cell disease

recessive; red blood cells sickle (abnormal shaple with pointed ends); causes damage to organs

Achondroplasia

dominant; abnormal cartilage formation; dwarfism

Huntington's disease

Dominant; neurons degenerate; causes mental and physical deterioration; symptoms appear anytime from late childhood to middle age.

nondidjunction

an instance wen two pairs of homologous chromosomes or sister chromatids fail to separate during Anaphase I or II. Leads to abnormal gamets with too many or too few chromosomes.

Karyotype

the analysis of chromosomes. count the number and observing the size of the chromosomes. usually performed in utero (amniotic fluid tested) but can be performed on other tissues such as blood and bone marrow.

Down Syndrome

an extra copy of chromosome 21 (trisomy 21); delayed cognitive ability, oblique eye shape, flat nasal bridge.

Edwards syndrome

an extra copy of chromosome 18. structural heart defects, kidney defects, muscle dysfunction, widely spaced eyes, overlapping fingers (index with third and fifth with fourth)

Klinefelter syndrome

at least on extra copybof the X chromosome (XXY) male specific. reduced muscle strength, reduced testosterone production, increases height, broad hips, pronounced breasts, small testes, reduced fertility.

Patau Syndrome

Trisomy 13;cleft palate, as well as eye, brain, and circulatory defects.

Ring 18

ring shaped chromosome 18, resulting from deletion of chromosome tips. eye folds, increased distance between eyes, low set ears, heart defects

Triple X Syndrome

and extra copy of the X chromosome (XXX) female specific. mild or non phenotype manifestations; healthy with normal fertility. increased risk of delayed development.

Turner Syndrome

only one X chromosome (female specific) Only viable monosomy not resulting in death. reduced height, sterile, normal intelligence.

XYY syndrome

an extra copy of the Y chromosome (XYY) increased height, reduced cognitive ability, normal fertility

Genomics

the study of complete sets of genes in an individual and the interactions of these genes.