Lecture 1 Intro/fundamentals Flashcards
of chromosomes in a human?
46 total
23 pairs
what is a proteome?
complete set of proteins encoded by genome
presymptomatic genetic testing:
looks for genetic mutations rhat are highly _____.
they have a high ____.
example = _______
predictive of developing a disease (near 100%);
penetrance;
Huntington disease
susceptibility testing:
look for genetic mutations that confer a high ____
2 examples
risk of developing disease (not 100% predictive);
ApoE in alzheimers, BRCA1 and 2 in breast cancer
what does ELSI stand for
ethical, legal, and social implications
50% of first trimester abortions are due to what?
chromosomal disorders
DNA replication is a ______ process that occurs in the ___ to ____ direction
semi-conservative;
5, 3
which DNA base pair has a higher melting temperature? why?
G-C;
it has 3 H bonds vs A-T (which as 2 bonds)
a nucloeosome is made of DNA wrapped around ____ _____ charged histones
8 positively
somatic cells have ____ chromosomes and are ____ploid;
gametes have ____ chromosomes and are ___ploid
46, diploid;
23, haploid
where is the centromere located in….
metacentric chromosomes?
acrocentric chromosomes?
in the middle (ie p and q arm are equal);
at one of the ends (ie v small short arm (p arm))
as cells divide, ____ begin to shorten. what prevents this?
telomeres;
telomerase (adds DNA to 3’ ends of chromosomes)
exons vs introns:
which are coding sequences?
which are non-coding segments?
are promoters located at the 5’ or 3’ end of genes?
exons;
introns;
5’
the ____ strand of DNA is the template for transcription.
where does transcription occur?
anti-sense;
in the nucleus
where does translation occur?
what end of mRNA does it start with?
cytoplasm;
5’ end
mutations:
nucleotide substitution, codes for same AA = ___;
nucleotide sub, forming an early stop codon = ____;
nucleotide sub, forming a different AA = ____;
what mutation is considered the most damaging?
silent;
non-sense;
missense;
frame-shift
mitosis:
____ replication(s) and ____ cell division(s);
cells end up being __n
1, 1;
2
ie gives rise to 2 identical sister chromatids
during what phase of the cell cycle are chromosomes typically visible?
mitosis (rest = interphase and not really visible)
mitosis:
prophase = ____ of chromosomes and formation of _____.
____: nuclear membrane dissolves, _____ attach to spindle
condensation, spindle;
prometaphase, kinetochores
mitosis:
metaphase =
anaphase =
telophase = chromosomes begin to ____, nuclear membrane reforms
chromosomes line up at equatorial plate ;
chromosomes separate at centromeres;
de-condense
"metaphase = MEET" "anaphase = AWAY"
the ____ regulates the metaphase to anaphase transition. it prevents _____ chromosome segregation
spindle assembly checkpoint; unequal
cell cycle in always dividing cells:
mitosis –> ______ –> ____ –> ____
G1, S phase, G2
meosis:
___ replication phase(s), ____ division phase(s);
final products are ___n
1, 2;
1 (ie 23 chromosomes)
meiosis:
homologs segregate during ____.
crossing over occurs during _____. is this before or after replication?
meosis 1 ;
meiosis prohpase 1, after (ie 4 strand stage)
meiosis 1 = _____ division, ie homologous centromeres separate at anaphase 1;
meiosis2 =
_____ division; sister chromatids separate
reductional;
equatorial (like mitosis)
what holds homologs/sister chromatids together in M1?
cohesin complex aka chiasmata
chromosome non disjunction occurs if:
- no ____ formation
- _____ at sub-optimal location ie v far away from centromere
chiasmata;
crossing over
spermatogenesis begins at _____.
puberty
oogenesis: meiosis begins when? what phase is meiosis arrested in? what is this called? meosis II is arrested in \_\_\_\_ until \_\_\_\_\_
during fetal life;
prophase 1;
dictyotene;
metaphase 2, fertilization
ovulation:
- ____ forms, homologs separate
- one set of homologs will assemble on the ___ ___
- other homolog is ejected and is now called a _____
spindle;
MII spindle;
polar body
for one primary oocyte, how many polar bodies are formed?
3.
1 ovum
