1. In sexually reproducing species, the number of chromosomes in a zygote is
diploid as a direct result of what 2 processes?
The number of chromosomes in a zygote is diploid as a result of mitosis which creates
46 chromosomes.
2. What is the relationship between chromosomes, genes, and nuclei?
Chromosome: genetic information bundled into packages of DNA.
Gene: sequence of DNA nucleotides that codes for specific protein or RNA
molecules.
Nuclei: The center of the nucleus which contains the DNA of the cell
3. A polypeptide is made at a ribosome attached to the ER. Trace the pathway it
follows to leave the cell.
The polypeptide leaves the cell through facilitated diffusion. The
polypeptide moves down its concentration gradient.
4. To produce large tomatoes that are resistant to cracking and splitting, some
seed companies use the pollen from one variety of tomato plant to fertilize a
different variety of tomato plant. What is this process an example of?
This process is an example of artificial selection which can also be known as selective
breeding. Artificial selection is when humans choose the best choices on purpose in an
environment to reproduce.
5. What is the relationship between cells, DNA, and proteins?
Cells contain organelle structures such as DNA and proteins. DNA is found in the
nucleus of the cell. Proteins help cells function while DNA codes for cells.
6. What is true of both mitosis and meiosis?
Both mitosis and meiosis are types of cell division and both follow duplication of
chromosomes. They also both contain prophase, metaphase, anaphase, telophase, and
cytokinesis.
7. What causes an extra chromosome to be present?
A duplication mutation causes an extra chromosome to be present.
8. A point mutation occurs during DNA replication; more specifically, a
substitution of an A for a T occurs. There is no change in the amino acid
sequence of the polypeptide. What type of mutation is this?
This type of mutation is known as silent mutation since there is a substitution but the
amino acid sequence is not changed.
9. The diagram below represents four different species of bacteria.What species
would have the best chance of survival if there was a change in the
environment? Why?