Answer:
The binding of chemical messengers to receptors often results in a shape change, which affects receptor function.
Explanation:
Binding of specific chemical messengers to the corresponding receptors of target cells brings about change in the shape of the receptors. This structural change in the receptor results in the generation of the desired response. It reflects how the form and specific configuration of substances or biomolecules affect their functions.
For example, binding of neurotransmitters to the receptors present on neurons opens the associated ligand-gated ion channels to allow the movement of specific ions through it. In the absence of bound ligand, these channels are present in a closed conformation.
Answer:
During exercise, your heart typically beats faster so that more blood gets out to your body. Your heart can also increase its stroke volume by pumping more forcefully or increasing the amount of blood that fills the left ventricle before it pumps.
Answer:
Option B, not phosphorylated; inhibited
Explanation:
Glucose 6 acts as a catobolite repressant . A catobolite repressant which is usually a carbon compound inhibits the operon transcription. In the presence of glucose -6, unphosphorylated enzyme IIAGlc inhibits the transportation system and hence prevents the utilization of lactose. Glucose‐6‐phosphate and other non‐PTS carbon causes inducer exclusion thereby leading to dephosphorylation of enzyme IIAGl without getting transported.
Hence, option B is correct
The correct answer is: a. A site in DNA that recruits the RNA Polymerase
Promoters are regions of DNA molecule located near the transcription start codons of genes, usually upstream on the DNA with the function to initiate DNA transcription. Promoters contain specific DNA sequences (e.g. TATA boxes) that are binding sites for the enzyme RNA polymerase and transcription factors that recruit RNA polymerase. Transcription factors can regulate gene expression and act as activators or repressors depending on sequences that attach to specific promoters.
