Answer:
a. the RNA polymerase undergoes abortive initiation prior to promoter clearance
Explanation:
In eukaryotes the 3' end of the mRNA is polyadenylated to protect the mRNA from degradation.
In eukaryotes, a modified guanine cap is added to the 5' end of the mRNAd to protects the transcript from being broken down.
Most bacterial RNA transcripts do not undergo splicing.
The nucleosome is the basic unit of chromatin repeat in eukaryotes.
The pluripotent, undifferentiated cells in the bone marrow that give rise to the formed elements are called stem cells.
Pluripotent stem cells have the ability to undergo self-renewal and to give rise to all cells of the tissues of the body. However, this definition has been recently complicated by the existence of distinct cellular states that display these features.
There are two types of pluripotent stem cells :
- Embryonic stem cells (ESCs)
- Induced pluripotent stem cells
Embryonic stem cells are derived from the inner cell mass (ICM) of pre-implantation embryos and can be indefinitely maintained and expanded in the pluripotent state in vitro. Pluripotent stem cells can also be obtained by inducing dedifferentiation of adult somatic cells through a recently developed in vitro technology, known as cell reprogramming.
Similarly to Embryonic stem cells , Induced pluripotent stem cells can be expanded indefinitely and they are capable to differentiate in all the derivatives of the three germ layers.
Another intriguing features of being pluripotent is its reliance on gene expression heterogeneity.
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Answer:
A- A pH change can cause the enzyme to change its shape
Explanation:
A rise or fall in the pH of the medium from the optimum of pH 7 usually affect the enzymes' active sites of and therefore the shape and the rate of enzyme activity.
Assuming the pH is too low, the enzyme medium becomes acidic;Acidosis. The high Hydrogen ions concentration interacts with the R-groups of the amino acids moiety of the enzymes, this interaction affects the ionization of the R-groups, disrupting the ionic bonding holding these R-groups in shape.
This results in loss of the 3-Dimensional shape arrangements of the protein molecule and therefore of the active sites. Since active sites of enzymes determines the specificity of the <u>enzymes substrate- complex </u> to give <u>enzyme-product complex,</u> the catalytic activity of the enzymes decreases, <u>the rate of reaction decreases,and products formation stops, and the reaction also stops.</u>
The same is applicable to extremely high pH=Alkalosis.
However, the effective buffer system of the body prevents this scenarios from happening in real sense in the body. Through mopping by the haemoglobin, excretion by the kidney, etc
<span>George Simmel was a pioneer in sociological studies due to the fact that he developed the concept of the sociological imagination, and believed that societies can be understood through an empirical scientific approach known as positivism which is still used in research today.</span>
Answer:
As the amount of impervious paved surfaces increase, watersheds become more vulnerable to pollutants. When rains fall on a conventionally paved impervious surface, the precipitation is generally directed down storm drains, which can result in flooding and overwhelming the storm water management system.
Explanation:
