Answer:
The main function of the RB protein is to inhibit the transition from the G1 to S phase. Its activity depends on its phosphorylation state: if RB is not phosphorylated (active state), it is bound to the transcription factor E2F, preventing its translocation to the nucleus and the activation of genes necessary for DNA synthesis; and if it is phosphorylated, by cyclin-CDK complexes, E2F is released and cell proliferation occurs.
Explanation:
Retinoblastoma (Rb) was the first tumor suppressor described and, as we know today, mutations in its structure determine a large number of cancers. Structurally, we speak of a large and multifunctional protein; which is organized in different domains. The activity of this protein is regulated, mainly, by phosphorylation at multiple sites described over the years and is involved in control mechanisms of the cell cycle, apoptosis and senescence.
Answer:
Correct
Explanation:
Homeostatic is nothing but ability of a system or living organism to manipulate its internal environment to maintain a stable equilibrium, for example the ability of warm-blooded animals to ascertain a constant body temperature.
The Homoeostatic feedback mechanism has three basis components and they are independent to one another.
These components are receptor, effector and integrating center. The function of receptor is to sense external stimuli and send information to integrating center. The integrating center generally hypothalmus in brain sends this signal to effector for example an organ to react to the stimuli.
So, the order in a homeostatic feedback system stimulus, receoptor, control centre, effector is correct.
The chemical tags that are attached to DNA, known as the epigenome, can potentially be altered by the environment. These tags change the amount of protein that is produced from the genes by making them more or less active.
- Traits are frequently influenced by environmental factors rather than genetics. Although not always. Sometimes a gene's DNA sequence or degree of activity is altered by the environment.
- The proteins that a gene produces can be replaced by either of these effects, which in turn impacts characteristics.
- The nucleotide sequence of a gene may alter as a result of some harmful environmental influences. DNA strands, for instance, can be damaged by UV light.
- Certain pollutants, such as those found in plastic and cigarette smoke, can change how DNA bases behave chemically, allowing one DNA base to stand in for another.
To know more about DNA check the below link:
brainly.com/question/16099437
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Answer:
During the S phase at interphase in meiosis I
Explanation:
During the S (DNA synthesis) phase at interphase in meiosis I, DNA replication occurs here where the chromosomes are doubled. This phase does not occur in meiosis II. At the end of meiosis II, the chromosome number becomes halved in the sex cells. The cell just goes on to divide to ensure haploidy of chromosomes in the gametes such that the sperm from the male and egg from female are both haploid. Fertilization brings about diploidy of the zygote itself
