Practice exam cell biology
In growing plant cell there is always endocytosis, because in this manner the
excess imported plasma membrane is transported back into the cell.
Plant cells have a cell wall consisting of cellulose microfilaments embedded in a
matrix of hemicellulose and pectin molecules.
Plasmolysis occurs when a plant cell is immersed in a solution with a high salt
concentration. This is in a hypertonic solution, the cell will lose water because it
has too much water inside the cell if you compare to the outside.
Oryzalin inhibits microtubules polymerization in plant cells, when this is used in
Arabidopsis (closely related to crop plants like cabbage and broccoli) roots the
cell division will cease.
The red color of a flower can only be synthesized if several enzymes are
present which together synthesize anthocyanin (the blue, violet, or red
pigment in plants). Someone wants to use techniques to grow white flower.
The synthesize of additional mRNA for these genes WONT work but blocking
transcription and translation for these enzymes will and mutating the genes
coding for these enzymes also will work.
Microtubules don’t nucleate/develop in telomeres. They do in centrosomes,
basal bodies (cell organelle at the base of a flagellum or cilium) and in
kinetochores (protein complex assembled on the centromeric region of DNA).
Telomerase binds to the 3’ end of telomeres by DNA-RNA base pairing. So it
adds nucleotides to the 3’ end of a DNA strand. Telomerase activity is exhibited
in gametes and stem and tumor cells. Telomeres are found at the end of a
chromosome which protect the genetic information. They have the sequence
TTAGGG. If a genetic mishap turns telomerase production on, it can cause
abnormal cells to multiply and form tumors. Cancer cells often have
paradoxically shorter telomeres.
When in a cell telomerase is active, telomere length is not correlated with the
number of divisions the cell underwent.
The nucleus is enveloped by two membranes.
In growing plant cell there is always endocytosis, because in this manner the
excess imported plasma membrane is transported back into the cell.
Plant cells have a cell wall consisting of cellulose microfilaments embedded in a
matrix of hemicellulose and pectin molecules.
Plasmolysis occurs when a plant cell is immersed in a solution with a high salt
concentration. This is in a hypertonic solution, the cell will lose water because it
has too much water inside the cell if you compare to the outside.
Oryzalin inhibits microtubules polymerization in plant cells, when this is used in
Arabidopsis (closely related to crop plants like cabbage and broccoli) roots the
cell division will cease.
The red color of a flower can only be synthesized if several enzymes are
present which together synthesize anthocyanin (the blue, violet, or red
pigment in plants). Someone wants to use techniques to grow white flower.
The synthesize of additional mRNA for these genes WONT work but blocking
transcription and translation for these enzymes will and mutating the genes
coding for these enzymes also will work.
Microtubules don’t nucleate/develop in telomeres. They do in centrosomes,
basal bodies (cell organelle at the base of a flagellum or cilium) and in
kinetochores (protein complex assembled on the centromeric region of DNA).
Telomerase binds to the 3’ end of telomeres by DNA-RNA base pairing. So it
adds nucleotides to the 3’ end of a DNA strand. Telomerase activity is exhibited
in gametes and stem and tumor cells. Telomeres are found at the end of a
chromosome which protect the genetic information. They have the sequence
TTAGGG. If a genetic mishap turns telomerase production on, it can cause
abnormal cells to multiply and form tumors. Cancer cells often have
paradoxically shorter telomeres.
When in a cell telomerase is active, telomere length is not correlated with the
number of divisions the cell underwent.
The nucleus is enveloped by two membranes.
