Answer:
can you put this in English pls
Answer:
C) Through genomic imprinting, methylation regulates expression of the paternal copy of the gene in the brain.
Explanation:
The pattern of gene expression wherein either paternal or maternal gene is expressed in specific cells while the other one is prevented from expression is known as genomic imprinting.
In the given example, the maternal copy of the gene on chromosome 15 is expressed in brain cells while its paternal copy is not expressed in these cells. Hence, the pattern of expression of this gene is regulated through genome imprinting. One of the mechanism is methylation of cytidine residues of CpG islands of the DNA that are more frequently present within promoters of the genes.
When the cytidine residues of these sequences are methylated into 5-methylcytidine, the transcription factors do not bind to these promoters preventing the expression of these genes.
Hence, methylation of cytidine residue in CpG islands of the promoters of the gene present on chromosome 15 could have silenced its expression in brain cells.
Answer: 37 chromosomes.
Explanation: As is typical of mammals, llamas are diploid organisms, meaning that the number of chromosomes in each of their somatic cells is exactly twice of that found in the gametes (the so-called haploid number, referred to as "n"). If a particular species has 74 chromosomes in its somatic cells, we should expect to find 74/2=37 chromosomes in each gamete.
Answer:
C. NAD⁺
Step-by-step explanation:
NADH is oxidized to NAD⁺ in Complex I of the Electron Transport Chain.
NADH ⟶ NAD⁺ + H⁺ + 2e⁻
The electrons continue through the Electron Transport Chain, and the NAD⁺ is used in three places during the Krebs Cycle.
(a) Isocitrate to oxalosuccinate
Isocitrate + NAD⁺ ⟶ oxalosuccinate + NADH + H⁺
(b) α-Ketoglutarate to succinyl-CoA
α-ketoglutarate + NAD+ + CoA → succinyl CoA + CO₂ + NADH
(c) Malate to oxaloacetate
Malate + NAD⁺ ⟶ oxaloacetate + NADH + H⁺
The NADH produced by these three reactions can then be used by Complex I in the Electron Transport Chain.
