Answers:
a) carcinogenic
b) anti-carcinogenic
c) carcinogenic
d) carcinogenic
e) carcinogenic
f) anti-carcinogenic
g) anti-carcinogenic
h) anti-carcinogenic
Explanation:
Cyclins are proteins that regulate the progression through the cell cycle, i.e., the transition of G1 to S phase. It is well known that high cyclin expression may lead to cell proliferation states, which is closely associated with cancer progression. Moreover, the blockage of cyclins may have an anti-carcinogenic effect by inhibiting the progression through the cell cycle. MAP kinases are serine/threonine kinases that regulate the progression through the cell cycle by phosphorylating a variety of substrates during cell proliferation. In consequence, phosphatases that inactivate MAPK kinases (i.e., by dephosphorylation) may have an anticarcinogenic effect. The p53 is a tumor suppressor protein involved in diverse cellular processes including DNA repair, cycle arrest and programmed cell death. This protein (p53) is activated by phosphorylation at target residues and phosphatases inactivate it, thereby the blockage of its degradation may have an anticarcinogenic effect. Oncogene activation (i.e., the expression of oncogenes), may alter diverse cellular processes including DNA replication, and thereby may lead to cancer development. The G-protein α subunit is a GTPase that hydrolyses GTP and thus has a major role in controlling the kinetics of the G-protein signaling cascade. Platelet-derived growth factor receptors (PDGFR) are kinase receptors that play roles in regulating cellular differentiation, cell proliferation and cell growth. PDGFR receptors are present on the surface of normal cells, however, it has been shown that mutations of the PDGFR genes that lead to their high expression lead to uncontrolled cell growth and consequently cause cancer (i.e., by increasing PDGF signaling).
C. Increased genetic variation
Answer:
1. chromosome: tight coils of DNA
2. Eukaryote: a cell that has a membrane-bound nucleus
3. Gene: a specific sequence of DNA nucleotides that carry hereditary traits
4. Prokaryote: a cell whose nucleus is not bound by a membrane
5. Trait: genetic characteristic of an individual
Explanation:
Chromosomes are the thread-like structures that appear during cell division. Each chromosome is made up of DNA tightly coiled with its packing proteins.
A cell is defined as eukaryote or prokaryote on the basis of the presence of a membrane-bound nucleus. The cells that lack the membrane-bound nucleus and other membrane-bound organelles are called prokaryotic cells. Example: bacteria.
The cells that have a membrane bound nucleus in which DNA is present are called eukaryotic cells. Example: Plant cells.
A stretch of DNA that code for a particular protein and thereby regulate specific genetic trait is called a gene. Genes are present on chromosomes and are carried from one generation to next to maintain the genetic traits.
The features of living beings regulated by the gene are called trait. Example: skin color, eye color, etc.
