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3 years ago

Who developed protein crystallography and discovered the structure of vitamin b12?

1 answer:

6 0

Dorothy Mary Crowfoot Hodgkin was the first to develop protein crystallography and she won Nobel Prize for that discovery ( third woman to win the Nobel Prize in Chemistry). Hodgkin confirmed the structure of penicillin but also realized the structure of vitamin B12 by x-ray crystallography analysis. She advanced the classical technique of X-ray crystallography.

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Plant hormonal regulation differs from animal hormonal regulation in that _____. plant hormonal regulation differs from animal h

Pani-rosa [81]

I believe that plant hormonal control differs from animal hormonal control in that there are no separate hormone-producing organs in plants as there are in animals. Hormones regulate cellular processes in targeted cells locally and moved to other locations, in other function parts of the plant. Hormones also determine the formation of flowers, stems, leaves, the shedding of leaves, and the development and ripening of fruit. Plants unlike animals they lack glands that produce and secrete hormones and instead each cell is capable of producing hormones.

7 0

3 years ago

______ is the process by which nerve cells are coated with far cells that enhances the speed and efficiency of the information t

givi [52]

Answer:

Myelination

Explanation:

The covering of myelin around the axons is called the myelin sheath. This myelin sheath helps in transfer of information faster and also in complex processes of the brain. The process of myelination begins in the PNS (peripheral nervous system).

The myelinated section are seperated from each other with a gap called nodes of ranvier. Glial cells (oligodendrocytes) forms the myelin sheath in the central nervous system and schwann cells (glial cells) forms the myelin sheath in peripheral nervous system. The propagation of electrical impulse in the myelinated fibers is by saltatory conduction that is from one node to another.

5 0

3 years ago

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When a living organism dies, it stops taking in new carbon. Thus, as the radioactive carbon-14 decays, the ratio of carbon-12 to

Alexxandr [17]

Answer: The fossil is 11459 years old.

Explanation:

Half-life of carbon-14 = 5700 years

First we have to calculate the rate constant, we use the formula :

$k=\frac{0.693}{5700\text{years}}$

$k=1.21\times 10^{-4}\text{years}^{-1}$

Now we have to calculate the age of the sample:

Expression for rate law for first order kinetics is given by:

$t=\frac{2.303}{k}\log\frac{a}{a-x}$

where,

k = rate constant = $1.21\times 10^{-4}\text{years}^{-1}
t = age of sample = ?
a = let initial amount of the reactant = 100 g
x = amount decayed = 75 g
a - x = amount left after decay process = 100 - 75 = 25 g Now put all the given values in above equation, we get
[tex]t==\frac{2.303}{1.21\times 10^{-4}}\log\frac{100}{25}$

$t=11459years$

The fossil is 11459 years old.

4 0

3 years ago

What is measurement<br>

dusya [7]

Measurement is defined as the act of measuring or the size of something. An example of measurement means the use of a ruler to determine the length of a piece of paper. An example of measurement is 15" by 25".

3 0

3 years ago

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Albinism is a recessive trait in humans that is controlled by a single gene. How many recessive alleles must a person have to ha

olga_2 [115]

Answer;
Two recessive alleles are the number of alleles that a person must have to have albinism.

Explanation;
When a trait is recessive, such as albinism, an individual must have two copies of a recessive allele to express that particular trait. Recessive alleles are denoted by a lowercase letter , such as b versus B. Only individuals with a bb genotye will express a recessive trait, hence, the offspring must receive one recessive trait from each parent to exhibit the recessive trait.

6 0

3 years ago

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