Answer:
b. diffusion and osmosis across semi-permeable membranes
Explanation:
ATP (adenosine triphosphate) is a high energy carrying molecule in the system of living organisms. It posseses the ability to store and release energy for use by organisms during biochemical activities. However, some processes do not require ATP to occur and are called PASSIVE TRANSPORT while those that require energy (ATP) are called ACTIVE TRANSPORT.
In the above options, the processes listed as follows require ATP to occur:
- The active transport of glucose from the small intestine to the blood
- The movement of the flagella of sperm for motility
- Exocytosis of waste substances across a semi-permeable membrane
However, the diffusion and osmosis across semi-permeable membranes, which is a passive transport does not require ATP.
Answer:
Crossing over and random alignment are the events of meiosis-I that add new gene combinations to the gametes. Random fusion of male and female gametes is called random fertilization.
Explanation:
During the pachytene stage of meiosis-I, part of the chromatids of each of the homologous chromosomes of a bivalent is broken apart and exchanged. This exchange of the genetic material between the members of a bivalent is called crossing over. The recombinant chromatids formed by crossing over have new allele combinations that were otherwise not present in the parental chromatids.
During metaphase I, the homologous pairs are aligned at the cell's equator in a random manner. This means that either the paternal or maternal chromosome of a pair may face one or the other pole of the cell. The arrangement of chromosomes during metaphase-I determines whether the paternal or maternal chromosome of each pair would be distributed to one or the other pole of the cell. This random segregation creates new gene combinations in gametes.
All the gametes have equal chances of getting fused with a gamete from the opposite gender. This is called random fertilization and further adds variations.
Answer: silent mutation: a nucleotide base in a codon is replaced with a different base BUT the resulting amino acid isn’t affected.
Missense mutation: similar to a silent mutation, the only difference is that the switch of the nucleotide DOES result in a DIFFERENT amino acid
Nonsense mutation: a nucleotide base is changed, but that change results in a premature stop of translation
(Remember that after transcription, you are left with a strand of mRNA that Is then translated into a protein. The mRNA is read in increments of three nucleotide bases (A,U,G, or C) which is called a codon. That codon makes a single amino acid, and a strand of amino acids makes a protein)
