test 4 Flashcards
achondroplasia
Achondroplasia is the most common form of skeletal dysplasia, occurring in about one in every 40,000 births. Achondroplasia impairs the growth of bone in the limbs and causes abnormal growth in the spine and skull.
autosome
any chromosome that is not a sex chromosome.
Autosomal dominant disorders
Autosomal dominant is a pattern of inheritance characteristic of some genetic disorders. Genetic disorders that follow a pattern of autosomal dominant inheritance include:
Huntington’s disease.
Marfan syndrome.
Achondroplasia.
Autosomal recessive disorders
Autosomal recessive is a pattern of inheritance characteristic of some genetic disorders. Examples of autosomal recessive disorders include cystic fibrosis, sickle cell anemia, and Tay-Sachs disease.
BRCA1 and BRCA2
BRCA1 (BReast CAncer gene 1) and BRCA2 (BReast CAncer gene 2) are genes that produce proteins that help repair damaged DNA. Everyone has two copies of each of these genes—one copy inherited from each parent.
chromosome theory of inheritance
that genes are found at specific locations on chromosomes, and that the behavior of chromosomes during meiosis can explain Mendel’s laws of inheritance.
cri du chat
Cri du chat syndrome is a rare genetic disorder caused by missing pieces on a particular chromosome. It is not the result of anything the parents have done or failed to do. The characteristics of a newborn with cri du chat syndrome include a high-pitched cry, a small head and a flattened bridge of the nose.
crossing-over
the exchange of genes between homologous chromosomes, resulting in a mixture of parental characteristics in offspring.
Cystic Fibrosus
Cystic fibrosis is a disorder that damages your lungs, digestive tract and other organs. It’s an inherited disease caused by a defective gene that can be passed from generation to generation.
deletion
a type of mutation that involves the loss of one or more nucleotides from a segment of DNA.
duplication
type of mutation in which one or more copies of a DNA segment (which can be as small as a few bases or as large as a major chromosomal region) is produced.
genetic carrier
Carrier
A carrier, as related to genetics, is an individual who “carries” and can pass on to its offspring a genomic variant (allele) associated with a disease (or trait) that is inherited in an autosomal recessive or sex-linked manner, and who does not show symptoms of that disease (or features of that trait).
genetic linkage
the close location of genes or other DNA markers to each other on chromosomes. The closer the genes are to each other on a chromosome, the more likely they are linked or inherited together from parents to offspring.
Histone proteins
A histone is a protein that provides structural support for a chromosome.
Huntington’s disease
an inherited disorder that causes nerve cells (neurons) in parts of the brain to gradually break down and die.
Hemophilia A
a hereditary hemorrhagic disorder resulting from a congenital deficit of factor VIII that manifests as protracted and excessive bleeding either spontaneously or secondary to trauma.
independent assortment of chromosomes
The alleles of two (or more) different genes get sorted into gametes independently of one another.
inversion
An inversion in a chromosome occurs when a segment breaks off and reattaches within the same chromosome, but in reverse orientation.
locus
a term that we use to tell us where on a chromosome a specific gene is.
Muscular dystrophy
a group of diseases that cause progressive weakness and loss of muscle mass.
Nondisjunction
he failure of one or more pairs of homologous chromosomes or sister chromatids to separate normally during nuclear division, usually resulting in an abnormal distribution of chromosomes in the daughter nuclei.
Parkinson’s Disease
brain disorder that causes unintended or uncontrollable movements, such as shaking, stiffness, and difficulty with balance and coordination.
pedigree
a chart that diagrams the inheritance of a trait or health condition through generations of a family.
PKU disease
n inherited disorder that increases the levels of a substance called phenylalanine in the blood.
Prader- Willi Syndrome
is a genetic multisystem disorder characterized during infancy by lethargy, diminished muscle tone (hypotonia), a weak suck and feeding difficulties with poor weight gain and growth and other hormone deficiency.
random fertilization
during sexual reproduction, the male gamete and female gamete that fuse to produce an offspring are selected randomly from the pool of male and female gametes.
Red-Green color blindness
It makes certain shades of green look more red.
sex chromosome
a type of chromosome involved in sex determination.
sex-linked traits
hemophilia, red-green color blindness, congenital night blindness, some high blood pressure genes, Duchenne muscular dystrophy, and also Fragile X syndrome.7 days ago
somatic gene mutation
A somatic mutation describes any alteration at the cellular level in somatic tissues occurring after fertilization.
SRY gene
This protein is involved in male-typical sex development, which usually follows a certain pattern based on an individual’s chromosomes.
SWYR Syndrome
In Swyer syndrome, individuals have one X chromosome and one Y chromosome in each cell, which is the pattern typically found in boys and men; however, they have female reproductive structures . People with Swyer syndrome have female external genitalia and some female internal reproductive structures.
Tay Sacs Disease
A rare, inherited disorder that destroys nerve cells in the brain and spinal cord.
test cross
a test cross is a device that can be used to infer the Mendelian alleles present in parental gametes based on the observation of offspring phenotypes.
translocation
A translocation, as related to genetics, occurs when a chromosome breaks and the (typically two) fragmented pieces re-attach to different chromosomes.
Trisomy 21
Down syndrome
Turner’s Syndrome
Turner syndrome, a condition that affects only females, results when one of the X chromosomes (sex chromosomes) is missing or partially missing. Turner syndrome can cause a variety of medical and developmental problems, including short height, failure of the ovaries to develop and heart defects.
Klinefelter Syndrome
Boys with Klinefelter syndrome might have some or all of these physical signs: a taller, less muscular body than other boys their age. broader hips and longer legs and arms. larger breasts
Jacob’s disease XYY
taller than average height. low muscle tone, or muscle weakness (called hypotonia) very curved pinky finger
XXX Syndrome
a genetic disorder that affects about 1 in 1,000 females. Females normally have two X chromosomes in all cells — one X chromosome from each parent. In triple X syndrome, a female has three X chromosomes.
X-linked traits
X-linked, as related to genetics, refers to characteristics or traits that are influenced by genes on the X chromosome.
Y-linked traits
the Y chromosome also carries genes other than for sex determination. Hypertrichosis of the ears, webbed toes, and porcupine man are examples of Y-linked inheritance in humans.
Rosalind Franklin
Discovered the structure of DNA
James Watson and Francis Crick
Deciphered the physical structure. won the Nobel Prize for discovering that DNA is built from two helically
wound polynucleotides (the double helix).
What are the four nucleic acids?
thymine (T), cytosine (C), adenine (A) and guanine (G)
How does the double helix get formed
DNA is
deoxyribonucleic acid
that is composed of
nucleic acids
What is DNA’s 5-carbon sugar?
Deoxyribose
2 Nitrogenous bases?
Pyrimidines and Purines
What are the bonding pairs of DNA
A to T and C to G
What does the double stranded DNA contain?
One strand contains the code and the other strand contains the template for the code
What do the two strands of DNA need to form hydrogen bonds?
they need to run antiparallel
What is it called when additional hydrogen bonds cause the DNA strands to
twist around each other
double helix
histone proteins
Short lengths of DNA are wound
around histone proteins to create
a bead-on-a-string structure that
is further compressed into a
looped fiber
What happens to DNA during cell division?
During cell division, DNA
condenses into shorter, thicker
chromosomes, the highest level of
packing a chromosome can
acquire.
What is referred to as a “loose ball of yarn?” It is in eukaryotes
chromatin
Where does DNA store information?
the Order of the Bases
in the Polynucleotide Chain
Genetic Variation
Differences in nitrogen base
sequences in DNA account
Why is one gene different from the other
because the two have different DNA nucleotide sequences.
Euchromatin
is the coding region of the chromosome; approximately 1 % of
the nitrogen bases
Promoters
provide binding sites for the protein machinery that carries out
transcription. Promoters are typically found just ahead of the gene on the
DNA strand.
Enhancers
provide binding sites for proteins that help activate
transcription. Enhancers can be found on the DNA strand before or after
the gene they control, sometimes far away.
Silencers
provide binding sites for proteins that repress transcription. Like
enhancers, silencers can be found before or after the gene they control
and can be some distance away on the DNA strand.
Insulators
provide binding sites for proteins that control transcription in a
number of ways. Some prevent enhancers from aiding in transcription
(enhancer-blocker insulators). Others prevent structural changes in the
DNA that repress gene activity (barrier insulators). Some insulators can
function as both an enhancer blocker and a barrier.
Noncoding DNA
is DNA that does not code for any kind of functional RN
Noncoding DNA that separates one gene from another is called
spacer dna
Transposons
are sequences that can move from one position on a chromosome to another,
or even from one chromosome to another, and may disrupt a gene’s function in the process
Introns
are noncoding sections interspersed with the coding regions of a gene or exons.
