Unit 3 Test study guide Flashcards
(22 cards)
The process of signal transduction usually begins when
when the signal molecule changes the receptor protein in some way
Most signal molecules
- bind to specific sites on receptor proteins in a membrane
- are water soluble
The signal transduction pathway in animal cells that use epinephrine
activates the breakdown of glycogen in liver and skeletal muscle cells.
Testosterone functions inside a cell by
binding with a receptor protein that enters the nucleus and activates specific genes.
is dATP considered a second messenger?
no
What is a second messenger molecule?
A small, non-protein based molecule that in response to a external signal is produced in or
released into the cytoplasm of a cell; the second messenger molecule binds to target proteins
and activates them amplifying the signal transduction cascade; examples are cyclic AMP, Ca++
and IP3
What is meant by amplification of a signal transduction cascade?
That a single binding event on the cell surface (i.e. hormone binding to a hormone receptor) can
activate thousands of target enzymes/proteins that carry out a cellular response)
What is meant by ‘cross-talk’ in signal transduction events?
That two signaling pathways can merge or affect each other through mutual or unidirectional
inhibition or activation
The centromere is a region in which
chromatids are attached to one another.
What is the name for the special region on a duplicated chromosome that holds the sister
chromatids together?
centromere
If there are 20 chromatids in a cell, how many centromeres are there?
10
In which group of eukaryotic organisms does the nuclear envelope remain intact during
mitosis?
dinoflagellates, diatoms
What proteins are involved in controlling the cell cycle of eukaryotic cells?
Cyclin, which is a master regulator of the cell cycle and cyclin dependent kinases (CDKs);
maturation promoting factor MPF is a cycling-Cdk dimer upregulated during mitosis.
Which parts of a cell cycle mechanism are likely to be defective in cancer cells?
Cannot stop synthesis of cycling or Cdk proteins; cannot stop at checkpoints
How do the two members of a pair of homologous chromosomes differ from each other?
the precise sequence of the DNA within each of the chromosomes
In animals, meiosis results in gametes, and fertilization results in
zygotes
Crossing over occurs during which phase of meiosis?
prophase I
At the end of telophase I of meiosis and cytokinesis, there are
two haploid cells
An organism has a haploid chromosome number n = 4. How many tetrads will form during
meiosis?
4
Why is crossing over important in sexual reproduction?
It allows the exchange of genes between homologous chromosomes.
If a chromosome lacks certain genes, what most likely occurred?
A deletion
What is a genome?
The complete complement of an organism’s genes
