Answer:
From top to bottom, the vertebrae are:
Cervical spine: 7 vertebrae (C1–C7)
Thoracic spine: 12 vertebrae (T1–T12)
Lumbar spine: 5 vertebrae (L1–L5)
Sacrum: 5 (fused) vertebrae (S1–S5)
Coccyx: 4 (3–5) (fused) vertebrae (Tailbone)
Answer: b. The radius forms the point of the elbow
c. The radius articulates to the wrist closest to the thumb
Explanation:
Ulna and radius are the two bones of the forearm. These bones articulates with the humerus and carpels of the hand.
b. The radius forms the point of the elbow: The elbow joint is the hinge joint that forms between the proximal ends of the radius and ulna in the forearm and distal ends of the humerus. The radius forms a pointed end.
c. The radius articulates to the wrist closest to the thumb: The wrist forms a complex joint. It forms a transition between the hand and the forearm. The radial deviation in the wrist forms the basis for the movement of the tilting of the wrist joint towards the thumb.
A mutation which occurs when a base is introduced into the DNA sequence before transcription begins will lead to frame-shift of a single base on the DNA sequence resulting in nonfunctional protein from the transcribed mRNA.
Explanation:
This change either through addition or deletion of a single base in the codon sequences of the DNA will modify the amino acid codes and will result in nonfunctional proteins after transcription.
This mutation will just result in change of a single base, i.e., it would be added either to the enhancer region or the silencer region of the sequence before the promoter which initiates transcription.
The mRNA produced due to mutated DNA sequence after the deletion or insertion point will be read as out of frame thus resulting in nonsense protein.
The lymphatic vessels are thin-walled valvular structures, composed of lymphangions, which carry the lymph from the tissues, via the lymph nodes, to the bloodstream. For this reason, they are analogous to veins and venules.
The lymphatic network is present throughout the body with the exception of the central nervous system and non-vascularized tissues.
It is separated in two circuits: one for the upper right quarter of the body, and one for the rest.
The lymphatic channels join together to form lymphatic vessels more and more voluminous.
Finally, The lymph is drained by two large collectors:
* The right lymphatic canal
* The thoracic duct.
All lymphatics thus end up in the upper vena cava system by two separate circuits.
A bacterium has a faulty lac operon in which there is a structural defect in the operator. In this bacterium there is a structural problem with a segment of DNA that binds a repressor.
- A protein known as a repressor binds to an operator site. The operator in this instance (and numerous others) is a section of DNA that lies just downstream of the RNA polymerase binding site or overlaps with it (promoter). In other words, it lies between the operon's promoter and its genes.
- The repressor protein inhibits the synthesis of messenger RNA by attaching to the promoter region of the gene(s) (mRNA). The control of gene expression in cells requires repressor proteins.
- Thus, by physically impeding the RNA polymerase's ability to operate, these repressor proteins stop the gene from being transcribed.
To learn more about DNA.
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