Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
79 Cards in this Set
- Front
- Back
|
Genes
|
-the basic units of inheritance
-found in chromosomes -composed of sequences of DNA -are the blueprints for protein |
|
|
DNA
|
-primary constituent of chromatin
|
|
|
What are the 3 basic components of DNA?
|
1. sugar molecule (deoxyribose)
2. phosphate molecule 3. 1 of 4 nitrogenous bases |
|
|
What are the 4 nitrogenous bases
|
1. Cytosine
2. thymine 3. Adenine 4. Guanine |
|
|
How are the 2 strands of DNA held together in the double helix?
|
Weak hydrogen bond
|
|
|
Nucleotide
|
a DNA subunit containing deoxyribose, phosphate and one base
|
|
|
Adenine pairs with _______
|
thymine
|
|
|
Guanine pairs with ______
|
Cytosine
|
|
|
Polypeptide
|
intermediate protein compound, a single linear chain of amino acids
|
|
|
What are proteins composed of?
|
one or more polypeptide
|
|
|
amino acid
|
organic acid containing NH2
|
|
|
What are polypeptides composed of?
|
sequences of amino acids
|
|
|
codons
|
a series of 3 bases in DNA or RNA molecule that codes for a specific amino acid
|
|
|
Explain why genetic code is universal
|
all living organisms use the same DNA code to specify protiens except mitochondria
|
|
|
complementary base pairing
|
2 nucleotides on opposite side of DNA or RNA strand. Combined by hydrogen bond.
|
|
|
DNA polymerase
|
important enzyme in DNA replication. Travels along DNA strand and adds correct nucleotide free end of new strand. Also proofreads final product and corrects errors.
|
|
|
Mutation
|
any inherited alteration of genetic material
|
|
|
Base pair substitution
|
One base pair is replaced by another
|
|
|
Misense mutation
|
a type of base pair substitution. Results in a change in amino acid sequence. May have no consequence due to redundancy of genetic code.
|
|
|
Silent substitution
|
base pair substitution where amino acid change doesn't occur
|
|
|
Frameshift mutation
|
Insertion or deletion of one or more base pairs to DNA molecule. Can change entrie frame and greatly alter amino acid sequence.
|
|
|
mutagens
|
agents that increase the frequency of mutation
|
|
|
examples of mutagens
|
radiation-forms electrically charged ions that can chemically change DNA bases.
Chemicals-can change bases because they are chemically similar to DNA. *nitrogen mustard *vinyl chloride *alkylating agents *formaldehyde *sodium nitrite |
|
|
spontaneous mutation
|
mutation that occurs in the absence of exposre to mutagens.
|
|
|
mutational hotspot
|
area of the chromosome that have high mutation rates
|
|
|
DNA is formes and replicated in the ______
|
nucleus
|
|
|
Where does protein synthesis occur?
|
Cytoplasm
|
|
|
RNA
|
nucleic acid that's chemically similar to DNA. Mediates transcription and translation for protein formation.
|
|
|
How is RNA different from DNA?
|
1. ribose sugar molecule
2. uracil base not thymine base 3. single strand |
|
|
uracil pairs with _____
|
adenine
|
|
|
transcription
|
process by which RNA is synthesized from a DNA template and results is formation of mRNA
|
|
|
transcription process
|
1. DNA molecule
2. RNA polymerase binds to promoter site on DNA 3. RNA ppolymerase pulls apart DNA strands 4. exposed strand provides sequence for mRNA nucleotides 5. mRNA is complementary to DNa base. 6. transcription continues until termination sequence 7. RNA polymerase detaches and mRNA freed to move into cytoplasm |
|
|
heterogenous nuclear RNA
|
mRNA after it's first transcribed and an exact replica of the DNA sequence
|
|
|
What happens in eukaryotic cells after transcription before mRNA released into cytoplasm?
|
nuclear enzymes remove RNA sequences and splice together remaining sequences to form functional mRNA
|
|
|
intron
|
excised RNA sequences that are left in the nucleus
|
|
|
exon
|
RNA sequences left to code for proteins
|
|
|
translation
|
the process by which the RNA directs the synthesis of polypeptide
|
|
|
Where does protein synthesis occur
|
Ribosome
|
|
|
translatioon steps
|
1. ribosome binds to initiation site of mRNA
2. ribosome moves along mRNA codone by coden and binds tRNA to its surface for base pairing of tRNA and mRNA 3. as codon is processed a amino acid translated by interaction of mRNA and tRNA 4. ribosome provides enzyme that catalyzes the formation of bonds between the amino acids forming a polypeptide 5. translation occurs until termination sequence then everything separtes and polypeptide moves to cytoplasm |
|
|
tRNA
|
a cloverleaf strand of about 80 nucleotides that has a site for the attachment of an amino acid
|
|
|
anticodon
|
found on the tRNA and is the base pairing for mRNA to form amino acid
|
|
|
2 types of human cells
|
1. gametes
2. somatic cells |
|
|
gamete
|
sperm and egg cell
|
|
|
somatic cells
|
-all human cells except gametes.
-dipolid cell |
|
|
how many chromosomes in the nucleaus of a somatic cell?
|
46 (23 pairs)
|
|
|
diploid cells
|
chromosomes occur in pairs
|
|
|
how are new somatic cells formed?
|
mitosis and cytokineses (cytoplasm and nucleus replicated)
|
|
|
haploid cells
|
1 member of each chromosome pair for a total of 23 chromosomes
|
|
|
Meiosis
|
the process by which haploid cells are formed from diploid cells.
|
|
|
autosomes
|
chromosome that is not a sex chromosome. there are 22 of 23 chromosome are autosomes.
|
|
|
male sex chromosome
|
non homologous x and y
|
|
|
female sex chromosome
|
homologous x and x
|
|
|
karyotype
|
display of chromosomes. arranged from large to small.
|
|
|
how do you classify chromosomes?
|
position of the centromere
|
|
|
What is the leading known cause of mental retardation and miscarriage?
|
chromosome abnormality
|
|
|
euploid cells
|
cells that have a multiple of the normal number of chromosomes
|
|
|
polyploid cell
|
a cell with more than the dipolid number of chromosomes (>46)
|
|
|
triploidy
|
a zygote having having 3 copies of each chromosome. not compatible with life. (69 chromosomes)
|
|
|
tetraploidy
|
4 copies of each chromosome. (92 chromosomes)
|
|
|
aneuploid cell
|
a cell that doesn't contain a multiple of 23 chromosomes.
|
|
|
trisomy
|
an aneuploid cell that has 3 copies of 1 chromosome
|
|
|
monosomy
|
a lethal abnormality. an aneuploid cell with only 1 copy of a given chromosome
|
|
|
____ of chromosome material is more serious than ____ of material.
|
loss, duplication
|
|
|
True or False
Aneuploidy of sex chromosome is less serius than that of autosomes. |
True
|
|
|
zygote
|
cell formed by the union of two gametes
|
|
|
nondisjunction
|
an error in which homologous chromosomes or sister chromosomes fail to separate normally during meiosis or mitosis.
|
|
|
Which trisomies are seen in birth?
|
13, 18 and 21
|
|
|
partial trisomy
|
only an extra portion of a chromosome is present in each cell
|
|
|
chromosomal mosaic
|
trisomy in only some cells of the bosy. body has two different cell lines, each with a different karyotype.
|
|
|
Down syndrome
|
aneuploidy. trisomy 21st chromosome. usually from nondisjunction in formation of maternal egg.
|
|
|
down syndrome characteristics
|
-mental retardation c IQ 25-70
-facial appearance- low nasal bridge, epicanthal folds, protruding tongue and low set ears -poor muscle tone and short stature -congenital heart defects -prone to respiratory infections -increased risk of leukemia -ALZ by 40yo |
|
|
risk of downs syndrome _____ with maternal age.
|
increases
|
|
|
trisomy x
|
sex chromosome aneuploidy affecting 1:1000 newborn females
|
|
|
trisomy x characteristics
|
-no overt physical abnormality
-sterile -menstrual irregularity -mental retardation |
|
|
turner syndrome
|
female sex chromosome aneuploidy where there is only a single x chromosome. AKA 45x
|
|
|
turner syndrome characteristics
|
-sterile
-gonadal streaks instead of ovaries -gonadal streaks susceptible to cancer in mosaics c some y chromosome cells -short stature -webbing in neck of 1/2 cases -wide spaced nipples -coarctation (narrowing) of the aorta -edema of feet in newborns -sparse body hair -reduced carrying angle of elbow |
|
|
turner syndrome treatment
|
-estrogen to promote secondary sex characteristics
-human growth hormone to increase stature |
|
|
Klinefelter syndrome
|
sex chromosome aneuploidy. 47, xxy
-male appearance but sterile -gynecomastia -small testes -saparse body hair -some mental retardation -high voice -tall stature |
|
|
47, xyy karyotype
|
sex chromosome aneuploidy.
-taller than average -10-15 point reduction in IQ -prevalent in prison population. |
