Genetics Flashcards
The carrier of genetic information
Chromosome
An ordinary chromosome; does not determine sex
Autosome
Humans are ____, meaning there are two
of every general type of chromosome in
ordinary body cells—i.e. a homologous pair
diploid
– Have the same linear sequence of genes
– Look alike
– Pair during meiosis
Homologous chromosomes
The position of a gene on its chromosome; the position of a gene on the genetic map
Locus
The region or regions of a chromosome with which the spindle fibers become associated during mitosis and meiosis
Centromere
protect the tips of chromosomes
telomere
shorten with each cycle of cell division (age)
telomere
gametic number (eggs and sperm)
n
somatic number (ordinary body cells)
2n
chromatin
relaxed chromsomes
copying DNA to RNA (mRNA) in nucleus
transcription
assembly of new protein using mRNA
translation
contain 23 pairs of chromosomes (total = 46)
human somatic cells
The two chromosomes that make up each pair are called
homologous chromosomes
homologs
the cell is not dividing, but cell replicates DNA here
interphase
G1, S, and G2
interphase
replication of DNA occurs in
S phase
consists of a nuclear division (mitosis)
and a cytoplasmic division (cytokinesis)
to form two identical cells
Mitotic phase (Prophase, Metaphase, Anaphase, Telophase)
exit from cell phase
Go
the chromatin fibers change into chromosomes
Prophase
microtubules align the centromeres of the chromatid pairs at the metaphase plate
metaphase
the chromatid pairs split at the centromere and move to opposite poles of the cell; the chromatids are now called chromosomes
anaphase
two identical nuclei formed around the identical sets of chromosomes now in their chromatin form
telophase
When does cytokinesis occur
usually begins in late anaphase
plasma membrane constricts in middle forming….
cleavage furrow
___ begins when cytokinesis is complete
interphase
- the cell is not dividing
- The cell replicates its DNA in S Phase
- Consists ofthree phases, G1, S, and G2
interphase
the chromatin fibers change into chromosomes.
prophase
microtubules align the centromeres of the chromatid pairs at the metaphase plate.
metaphase
reproductive cell division that occurs in the gonads (ovaries and testes) that produces games with half the number of chromosomes
meiosis
gametes contain a single set of 23 chromosomes
haploid cells
restores the diploid number of chromosomes (46)
fertilization
begins with a diploid cell and ends with two cells having the haploid number of chromosomes;
Meiosis I
In ____ , each of the two haploid cells divides, and the
net result is four haploid gametes that are genetically different from the original diploid starting cell.
Meiosis II,
gametes are produced by
meiosis
is a reductive division from 2n to n
meiosis I
Meiosis I ends with __ haploid cells
2 haploid cells
Meiosis II ends with ___ haploid cells
4 haploid cells
crossing over happens here (exchanging genetic information)
Prophase I
formation of tetrads (post crossing over) occurs here
Prophase I
consists of decoupling each chromosome’s sister strands (chromatids), then segregating the DNA into two sets (each set having one of each homologue)
Meiosis II
In Meiosis II, Two haploid cells with replicated ___ ___ go to form four haploid cells with __, ___ molecules of DNAs
sister chromatids
single, unreplicated
What is the following: Chromatids of homologous chromosomes form chiasmata wherein matching regions break and then reconnect to the other chromosome.
crossing over
chiasmata is….
site of crossing over or where chromosomes touch / overlap
which chromosome determines sex in mammals?
23
in humans there are 22 pairs of _____ and one pair of ___
autosomes; sex chromosomes
How many sister chromatids in homologous chromosomes?
4 total chromosomes with two sets of sister chromatids
A person with the same alleles on homologous
chromosomes (for example, AA or aa) is said to be
____ for that gene
homozygous
An individual with different alleles on homologous chromosomes (Aa) is said to be _____ for that
gene (or trait, or protein… same thing)
heterozygous
The _____ refers to genetic makeup of an individual
genotype
the ____ refers to their physical or outward appearance (the expression of the gene)
phenotype
masks the other allele
dominant allele
is masked by the dominate allele
recessive allele
There are two antigens and two antibodies responsible for ABO types; name all four
Type A - has Anti-B antibody
Type B - has Anti-A antibody
Type AB - has neither antibody
Type O - - has Both Anti-B and Anti-A antibody
ABO type is determined by
glycocalyx carbohydrates
To determine the ABO type, blood is are mixed with different _____ of known type. Agglutination occurs when the red cell antigens (which are unknown) correspond to the ____ in the antisera (which are known). This is called forward typing.
antisera
antibodies
DD
Dwarfism
The most common cause of dwarfism is
achondroplasia
genetic disorders in bone or cartilage development causing dwarfism
(skeletal dysplasias such as achondroplasia)
Forms of extreme shortness characterized by proportional body parts usually have a hormonal or nutritional cause such as growth hormone deficiency
(AKA “pituitary dwarfism”)
85% of children with _____ are born to average size parents
achondroplasia
achondroplasia means a de novo mutation
mutation prior to conception
Punnet square
inheritance chart
aa would cause
albinism
The Punnett square gives the possible ____ and the ratio of their probabilities, from which _____ information can be derived.
genotypes
phenotype
_____ is when an individual is born
with chromosomes added or missing
Aneuploidy
In _____ the cells are missing 1
chromosome
monosomy
In _____ cells have an additional chromosome. A common trisomy is Down Syndrome (trisomy 21) where the cells have three of the number 21 chromosome
trisomy
Rh in Blood type - Considered as three closely linked genes, the gene of major importance is the Rh or D gene having the alleles
– D, dominant
– d, recessive
The major antigen Rh or D is the most common cause of hemolytic disease of the newborn (AKA erythroblastosis fetalis when the D antigen is involved)
Genotype Phenotypes for Rh
DD Dd dd
Rh positive Rh positive Rh negative
Hemolytic disease of the newborn is with __ mother and __ fetus; mother produces anti-Rh antibodies
Rh- mother
Rh+ fetus
treatment for mother is IgG anti-D antibodies
Rhogam
meiosis followed by spermatogenesis produces sperm with
X or Y chromosome
an persons sex is determined by the
father
all females oocytes are XX
True
fertilization with Y containing sperm produces a
male
sex linkage is synonymous with X linkage
true
X linkage refers to genes on the—
X chromosome
Males transmit X chromosomes only to
their daughters
father to son inheritance
heterogamete to heterogamete inheritance
(meaning “not coming apart”) is the failure of chromosome pairs to separate properly during cell division.
– Loss of a single chromosome through
nondisjunction results in a ____
– Gain of a single chromosome is a ____.
Nondisjunction
monosomy
trisomy
Karotype: 47, XX, +21 means
Trisomy 21
Termed Klinefelter’s syndrome, it is the most common human sex chromosome disorder. Symbology is 47, XXY. This is not hermaphroditism.
AKA XXY.
most common human sex chromosome disorder
klinefelters or 47, XXY (not hermaphroditism)
Termed Turner’s syndrome
AKA XO. or 45, XO
simple squamous where?
epithelial membranes and lines blood vessels
columnar where?
digestive tract and organs
pseudostratified ciliated columnar?
Upper respiratory tract i.e. trachea
transitional where?
bladder
cuboidal where?
ducts and sweat glands
