What did you do in lab?
purify samples isolated from the fat tissue of pigs, which will be useful to identify genes linked to obesity
What word
... [Show More] fits in the gap? When a gene is expressed... Is produced
mRNA
the first step in gene expression is the synthesis of ______. Therefore the amount of ______ of a specific mRNA reflects the gene expression level of the corresponding ______
mRNA; molecules; gene
all genes are expressed all cells. Is this statement true?
a. no, only half of them are expressed in all the cells
b. no, only genes that are relevant for that particular cell are expressed
c. that's true
d. no, all genes are only expressed in the young cells and then their expression level decreases
b
all cells/tissues have the same ______, but only some are expressed
genes
If mRNA from gene A is very abundant in the fat tissue from the obese pig and rare in the fat tissue of the lean pig it shows as that
a. gene A is less expressed in obese animals
b. gene expression is random
c. gene A is more expressed in obese animals
d. no conclusion can be drawn from this data
c
A high mRNA level reflects a ______ expression level. So, by comparing the levels of the same mRNAs in obese and lean individuals, we can identify genes that may influence obesity status
high
Why do we keep tissue samples for RNA work in liquid nitrogen (-196C)?
a. to deactivate the RNA
b. to keep the fat tissue from melting
c. to preserve the RNA, which quickly do grades at room temperature
d. to preserve the tissue structure
c
the RNA content in a cell...
a. includes only mRNA and tRNA
b. is restricted to mRNA
c. includes only coding mRNA
d. includes both coding mRNA and several types of non-coding RNA
d
The homogenization tube contains tiny ______ that bounce around when the tube is placed in the homogenizer. The collision of the ______ with the sample breaks down the tissue and ______ the cells
beads; beads; lyses
where is most of the mRNA located?
a. in the mitochondria
b. in the nucleus
c. in the cellular membrane
d. in the cytoplasm
d
The mRNA is synthesized in the _______ and then transported to the _______. We need to break the _______ _______ to extract the RNA from the tissue sample
nucleus; cytoplasm; cellular membranes
the lysis buffer used for RNA extraction contains...
a. guanidinium isothiocyanate and phenol
b. chloroform
c. isopropanol
d. none of these
a
Lysis buffer contains guanidinium isothiocyanate which ______ proteins and therefore _______ the RNAses and _______ the RNA. The phenol _______ hydrophobic molecules and _______ the cells
denatures; inactivates; stabilizes; dissolves; lyses
What does the lysate consist of?
a. RNA, DNA, proteins
b. intact cells
c. RNA and proteins
d. RNA, DNA, proteins, and cellular debris
d
We will use ______ to separate the lysate into three phases. The aqueous phase contains ______, the interphase contains ______, and the organic phase contains ______ and ______
chloroform; RNA; DNA; proteins; lipids
What do you measure at 230, 260, and 280 nm, respectively?
a. chemicals, RNA/DNA, and proteins
b. proteins, DNA and RNA
c. DNA, proteins, and RNA
d. RNA at all wavelengths
a
At 230 nm you measure ______ remaining in your sample, at 260 nm you measure ______ ______, and at 280 nm you measure ______
chemicals; nucleic acids; proteins
A 260/280 should be between 1.8 and 2.1. What does it mean if we have a 260/280 ratio that his lower than 1.8?
a. there are a lot of proteins in the RNA sample
b. there are some chemical remnants, e.g., phenol in the RNA sample
c. the RNA sample is very degraded
d. the RNA sample is very clean
a
what will a spectrophotometer measure?
a. purity and integrity
b. purity, integrity, and quantity
c. only purity
d. purity and quantity
d
an RNA ladder helps with the identification of the _____ of the RNA. The gel electrophoresis and RNA ladder are useful to check the _____ of your samples and preparation
size; integrity
What you see in the gel if the RNA is intact?
a. two bands corresponding to rRNAs and a third band corresponding to mRNAs
b. a smear
c. two bands corresponding to rRNAs
d. one band corresponding to all mRNAs
c
if you see two bands of intact ribosomal RNAs (28s and 18s), that indicates that your RNA is not ______
degraded
Highly expressed genes will be represented by more copies of the ______, and therefore will be sequenced ______ frequently. This will give us information about the level of ______ of different genes in the samples
transcript; more; expression [Show Less]