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Bio156

Terms

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GENES
UNIT OF INFORMATION FOR A HERITABLE TRAIT PASSED ON FROM PARENTS TO OFFSPRING
ALLELES
ONE OF TWO OR MORE MOLECULAR FORMS OF A GENE THAT ARISE BY MUTATION AND CODE FOR DIFFERENT VERSIONS OF THE SAME TRAIT.
HOMOZYGOUS DOMINANT
HAVING A PAIR OF DOMINANT ALLELES AT A GENE LOCUS (EXAMPLE AA)
HETEROZYGOUS
HAVING A PAIR OF NONINDENTICAL ALLELES AT A GENE LOCUS
PROBABILITY
THE CHANCE THAT EACH OUTCOME OF A GIVEN EVENT WILL OCCUR IS PROPORTIONAL TO THE NUMBER OF WAYS THE OUTCOME CAN BE REACHED
HOMOZYGOUS RECESSIVE
HAVING A PAIR OF RECESSIVE ALLELES AT A GENE LOCUS ( EXAMPLE Aa)
HYBRID OFFSPRING
OF A GENETIC CROSS, OFFSPRING HAVING A PAIR OF NONIDENTICAL ALLELS FOR A TRAIT.
F1
THE OFFSPRING OF THE INITIAL GENETIC CROSS
F2
THE OFFSPRING OF PARENTS WHO ARE THE FIRST FILIAL GENERATION FROM A GENETIC CROSS
GENOTYPE
GENETIC CONSTITUTION OF AN INDIVIDUAL; A SINGLE PAIR GENE PAIR OR SUM TOTAL OF AN INDIVIVDUAL'S GENES
PHENOTYPE
OBSERVABLE TRAIT OR TRAITS OF AN INDIVIDUAL THAT ARISE FROM GENE INTERACTIONS AND GENE ENVIRONMENT INTERACTIONS.
MONOHYBRID CROSS
INTERCROSS BETWEEN TWO F1 HETEROZYGOTES THAT ARE IDENTICAL FOR ONE GENE LOCUS; OFFSPRING OF PARENTS THAT BREED TRUE FOR DIFFERENT FORMS OF A TRAIT.
PUNNETT-SQUARE
CONSTRUCTION OF A SIMPLE DIAGRAM AS A WAY TO PREDICT PROBABLE OUTCOMES OF A GENETIC CROSS.
TESTCROSS
EXPERIMENTAL CROSS TO DETERMINE WHETHER AN INDIVIDUAL OF UNKNOWN GENOTYPE THAT SHOWS DOMINANCE FOR A TRAIT IS EITHER HOMOZYGOUS DOMINANT OR HETERZYGOUS.
THEORY OF SEGREGATION
(MENDELIAN THEORY) SEXUALLY REPRODUCING ORGANISMS INHERIT PAIRS OF GENES ( ON PAIRS OF HOMOLOGOUS CHROMOSOMES), THE TWO GENES OF EACH PAIR ARE SEPARATED FROM EACH OTHER AT MEIOSIS, AND THEY END UP IN SEPARATE GAMETES.
DNA FINGERPRINT
DNA fragments inherited in a Mendelian pattern that give each individual a unique identity.
gel electrophoresis
Laboratory technique used to distinguish among molecules. Applied electric field forces them to migrate through a viscous gel and distance themselves from one another by length, size, or electric charge
gene therapy
Generally, a transfer of one or more normal genes into an organism to correct or lessen adverse effects of a genetic disorder.
genetic engineering
Deliberately altering the information content of DNA molecules.
genome
All the DNA in a haploid number of chromosomes for a given species.
plasmid
A small, circular molecule of extra bacterial DNA that carries a few genes and is replicated independently of the chromosome.
PCR (POLYMERASE CHAIN REACTION)
A method of enormously amplifying the quantity of DNA fragments cut by restriction enzymes.
recombinant DNA technology
Procedures by which DNA molecules from different species are isolated, cut up, spliced together, and then enormously amplified to useful quantities.
restriction enzyme
One of a class of bacterial enzymes that can cut apart foreign DNA that infects a cell, as by viral attack. Important tool of recombinant DNA technology.
bacillus (bacilli)
Rod-shaped prokaryotic cell.
coccus (cocci
Spherically shaped prokaryotic cell.
epidemic
Rapid spread, then subsidence, of a disease within a population.
pandemic
An epidemic that breaks out in several countries at the same time.
pilus (pili)
Short, filamentous protein projecting above cell wall to help it adhere to surfaces.
pathogen
Any virus, bacterium, fungus, protistan, or parasitic worm that can infect an organism, multiply in it, and cause disease.
prion
Small infectious protein that causes rare, fatal degenerative diseases of nervous system.
spirillum (spirilla)
A corkscrew-shaped prokaryotic cell.
virus
A noncellular infectious agent made of DNA or RNA, a protein coat and, in some, an outer lipid envelope; it can be replicated only after its genetic material enters a host cell and subverts the host's metabolic machinery.
AIDS
Acquired immunodeficiency syndrome. A set of chronic disorders following infection by the human immunodeficiency virus (HIV), which destroys key cells of the immune system
antibiotic
[Gk. anti, against] A normal metabolic product of certain microorganisms that kills or inhibits the growth of other microorganisms.
endemic disease
A disease that occurs more or less continuously in a region
human immunodeficiency virus HIV
A retrovirus; the pathogen that causes AIDS
retrovirus
An RNA virus that infects animal cells and with reverse transcriptase creates an RNA template to synthesize a DNA molecule which integrates itself into the host’s DNA
reverse transcription
Assembly of DNA on a single-stranded mRNA molecule by viral enzymes.
sporadic disease
A disease that breaks out irregularly and affects relatively few people.
p (parent) generation
The designation for the parental generation in a genetic cross.
locus
The location of a particular gene on a chromosome.
dominant allele
In a diploid cell, an allele that masks the expression of its partner on the homologous chromosome.
What is an allele?
a version of a gene
The offspring of a homozygous dominant parent and a homozygous recessive parent will be heterozygous.

TRUE OR FALSE?
True
What is the possibility that the child of two heterozygous individuals for a particular trait will have the recessive phenotype?
25%
The rules of probability guarantee that the children of heterozygous individuals will have varying phenotypes.
TRUE OR FALSE?
false
What is a testcross?
use of an offspring's phenotype to determine a parent's genotype
Evidence for Mendel's "independent assortment" principle can be established using:
a dihybrid cross
What is independent assortment?
either copy of a gene may end up in a particular gamete
How many different gamete unions are possible in a dihybrid cross with two heterozygous parents for two particular genes?
16
What is the varying effect of a single gene called?
pleiotropy
Human blood type AB is an example of:
codominance
What is penetrance?
the probability that the individual who inherits a particular allele will also have the phenotype associated with it.
Which one of the following conditions is associated with alleles that are totally penetrant?
cystic fibrosis
All genes act independently.
TRUE OR FALSE?
FALSE
The field of medicine dedicated to examining how genetics can help physicians customize drugs for individual patients is known as:
pharmacogenetics
According to the latest estimates, approximately how many genes does a human have?
30,000
What are autosomes?
chromosomes that are the same in both sexes
Genetically, what is the result of crossing over?
genetic recombination
How many pairs of autosomes does a human somatic cell have?
22
In the preparation of a karyotype, the chemical colchicine is used to:
arrest mitosis at metaphase
What percentage of a man's sperm carries the Y chromosome?
50%
What process prevents females receiving a double-dose of their gene products?
X inactivation
Genetic recombination is promoted when:
genes are farther apart on the chromosome
If both parents are carriers of a recessive genetic disorder, what are the chances a child will be homozygous for the harmful allele?
25%
On average, how many harmful recessive alleles does each individual carry?
3 to 8
Which one of the following genetic disorders is autosomal dominant?

a. cystic fibrosis

b. achondroplasia

c. phenylketonuria

d. Tay-Sachs disease
achondroplasia
Which genetic disorder results in weakened connective tissue?

a. phenylketonuria

b.familial Hypercholesterolemia

c. Marfan syndrome

d. Huntington disease
Marfan syndrome
Which one of the following conditions is not an X-linked recessive trait?

a. Duchenne muscular dystrophy

b. hemophilia A

c. red-green color blindness

d. Tay-Sachs disease
Tay-Sachs disease
What kind of inheritance pattern transmits hemophilia A?

a. autosomal recessive

b. X-linked recessive

c. X-linked dominant

d. autosomal dominant
X-linked recessive
Pattern baldness is an example of:

a. sex-influenced inheritance

b. autosomal dominant condition

c. X-linked recessive inheritance

d. autosomal recessive condition
sex-influenced inheritance
What is a mutation?
a change in the nucleotides that make up a gene
What term describes a gamete missing one chromosome?
monosomy
A person with three copies of chromosome 21 will have
Down syndrome
Which one of the following characteristics is indicative of Klinefelter syndrome?

a. loose joints

b. webbed neck

c. weak muscle reflexes

d. low fertility
low fertility
DNA sequencing
A method used to determine the order of nucleotides in a DNA fragment.
If a man has hemophilia (an X-linked recessive trait) and his wife is homozygous for the normal allele,
a. all daughters will be carriers.

b. all sons will have hemophilia.

c. all offspring will have hemophilia.
all daughters will be carriers
An XXY male has
a. Turner syndrome.

b. Klinefelter syndrome.

c. Fragile X syndrome.

d. Down syndrome.
Klinefelter syndrome.
DESCRIBE THE LIFE AND MAJOR EXPERIMENTS OF GREGOR MENDEL
Mendel used the garden pea in his experiments.


This plant can fertilize itself; true-breeding varieties were available to Mendel.
*Peas can also be cross-fertilized by human manipulation of the pollen.
*Mendel cross-fertilized true-breeding garden pea plants having clearly contrasting traits (example: white vs. purple flowers).
Mendel's Theory of Segregation
1.that 2n organisms inherit two genes per trait located on pairs of homologous chromosomes.
2.During meiosis the two genes segregate from each other such that each gamete will receive only one gene per trait.
In an organism with a diploid chromosome number of 36, the chromosome number in gametes will be

a. 36.

b. None of the choices.

c. 72.

d. 18.
18
Crossing over occurs during

a. anaphase II.

b. telophase I.

c. prophase I.

d. metaphase II.
prophase I.
In humans, each diploid oocyte gives rise to

a. one ovum and three polar bodies.

b. four ova.

c. four polar bodies.

d. four sperm.
one ovum and three polar bodies
Sister chromatids are separated during
a. prophase I.

b. anaphase I.

c. anaphase II.

d. interphase.
anaphase II.
Paired homologous chromosomes are found at the spindle equator during

a. interphase.

b. metaphase I.

c. prophase I.

d. anaphase II.
metaphase I.
Monohybrid crosses
*Monohybrid crosses have two parents that are true-breeding for contrasting forms of a trait.

*One form of the trait disappears in the first generation offspring (F1), only to show up in the second generation.

*We now know that all members of the first generation offspring are heterozygous because one parent could produce only an A gamete and the other could produce only an a gamete.
Dihybrid Crosses
*two traits
*F1 would show both of the dominant alleles (example: all purple flowers and all tall).
*genes located on nonhomologous chromosomes segregate independently of each other and give the same phenotypic ratio as Mendel observed--9:3:3:1.
Codominance
In heterozygotes, simultaneous expression of a pair of nonidentical alleles that specify different phenotypes
An animal cell having two rather than one of each type of chromosome has ____ chromosome number.
a. diploid
b. haploid
c. normal gamete
d. both b and c
diploid
Generally, a pair of homolgous chromosomes___
a. carries the same gene
b. has the same length,shape
c. interacts at meiosis
d. all of the above
all of the above
Meiosis ___ the parental chromosome number.
a. double
b. reduces
c. maintains
d. corrupts
reduces
before the onset of meosis, all chromosomes are____.
a. condensed
b. released from proteins
c. duplicated
d. both b and c
duplicated
deletion
At cytological level, loss of a segment from a chromosome. At molecular level, loss of one to a few base pairs from a DNA molecule.
duplication
Gene sequence repeated several to many hundreds or thousands of times. Even normal chromosomes have such sequences
nondisjunction
Failure of sister chromatids or a pair of homologous chromosomes to separate during meiosis or mitosis. Daughter cells end up with too many or too few chromosomes.
translocation
Of cells, movement of a stretch of DNA to a new chromosomal location with no molecular loss. Of vascular plants, distribution of organic compounds by way of phloem.
contribution of Linus Pauling
discovered the helical structure of proteins in 1951
contribution of of Watson and Crick
discovered the structure of the master molecule of life--DNA
contribution of Rosalind Franklin
used X-ray diffraction techniques to produce images of DNA molecules.
What Are the 3 Components of nucleotide?
1.a five-carbon sugar--deoxyribose;
2. a phosphate group;
3. one of four bases--adenine (A), guanine (G), thymine (T), cytosine (C).
list the nitrogen bases found in DNA
adenine (A)
guanine (G)
thymine (T)
cytosine (C)
describe the structure of DNA
1. Single-ringed thymine was hydrogen bonded with double-ringed adenine, and single-ringed cytosine with double-ringed guanine, along the entire length of the molecule.

2.The backbone was made of chains of sugar-phosphate linkages.

3.The molecule was double stranded and looked like a ladder with a twist to form a double helix.
explain the significance of base pairing
The base pairing is constant for all species but the sequence of base pairs in a nucleotide strand is different from one species to the next.
DNA replication requires____.
a. free nucleotides
b. new hydrogen bonds
c, many enzymes
d. all of the above
all of the above
When DNA replication begins___.
a.the two DNA strands unwind
b. the two DNA strands condense for base transfers.
c. two DNA molecules bond
d. old strands move to find new strands.
the two DNA strands unwind from each other
Which of the following is not a component of a nucleotide?

a. pentose sugar

b. phosphate group

c. nitrogenous base

d. glycerol
glycerol
The presence of which of the following nitrogenous bases would indicate a nucleic acid is a molecule of DNA rather than RNA?

a. cytosine

b. thymine

c. adenine

d. uracil
thymine
Who was the first to isolate DNA from a nucleus?
Miescher
The five-carbon sugar in DNA is
deoxyribose.
Which of the following is not required for DNA replication?

a. RNA polymerase

b. DNA polymerase

c. free nucleotide

d. DNA ligase
RNA polymerase
Which nucleotide bases have a double-ring structure?

a. adenine and thymine

b. adenine and guanine

c. thymine and cytosine

d. cytosine and adenine
adenine and guanine
The phrase "semiconservative replication" refers to the fact that

a. DNA replication proceeds in only one direction.

b. Nucleotide triphosphates are required for DNA replication.

c. DNA replication requir
half of the parent strand is conserved during DNA replication.
The path from genes to proteins has two steps:
In transcription, molecules of RNA are produced on the DNA templates in the nucleus.


In translation, RNA molecules shipped from the nucleus to the cytoplasm are used as templates for polypeptide assembly.
The Three Classes of RNA
are?
1. Messenger RNA (mRNA) carries the "blueprint" for protein assembly to the ribosome.

2.Ribosomal RNA (rRNA) combines with proteins to form ribosomes upon which polypeptides are assembled
3. Transfer RNA (tRNA) brings the correct amino acid to the ribosome and pairs up with an mRNA code for that amino acid.
define Bacteria
prokaryotes--no nucleus or other membrane-bound organelles.
What type of epithelium lines blood vessels?

a. simple cuboidal

b. pseudostratified columnar

c. simple squamous

d. stratified squamous
simple squamous
Which types of epithelial cells have cilia to sweep mucus or other fluids?

a. simple squamous

b. stratified cuboidal

c. pseudostratified

d. simple columnar
pseudostratified
Which one of the following is not an exocrine gland?

a. sebaceous gland

b. sweat gland

c. pituitary gland

d. mammary gland
pituitary gland
The basement membrane situated below epithelial tissue does not contain cells.

TRUE OR FALSE?
true
Which one of the following connective tissues is not "specialized"?

a. ligament

b. bone

c. cartilage

d. blood
ligament
What type of connective tissue is described as "collagen fibers in parallel bundles"?

a. loose connective

b. dense, regular connective

c. cells embedded in pliable, solid matrix

d. dense, ir
dense, regular connective
Chondroblast cells are found in:

a. bone

b. adipose tissue

c. cartilage

d. blood
cartilage
What type of muscle tissue or tissues is found on artery walls?

a. cardiac muscle

b. smooth muscle and cardiac muscle

c. skeletal muscle

d. smooth muscle
smooth muscle
Outgoing messages from neurons are conducted by:

a. neuroglia

b. axons

c. astrocytes

d. dendrites
axons
Cylindrical arrays of protein are found in which type of cell junction?

a. gap junctions

b. tight junctions

c. adhering junctions

d. all of these choices
gap junctions
What type of membrane consists only of connective tissue?

a. serous

b. synovial

c. cutaneous

d. mucous
synovial
Which anatomical plane of symmetry divides the body into right and left halves?

a. transverse plane

b. frontal plane

c. midsagittal plane

d. superior frontal plane
midsagittal plane
Spaces between cells and tissues are filled with:

a. interstitial fluid

b. water

c. blood plasma

d. blood
interstitial fluid

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