Answer:
evolution of life on Earth
Explanation:
Life began on Earth at least 3.5 to 4 billion years ago, and it has been evolving ever since. At first, all living things on Earth were simple, single-celled organisms. Much later, the first multicellular organisms evolved, and after that, Earth's biodiversity greatly increased.
Answer:
a. movement can occur both upward and downward in the plant
Explanation:
The phloem loading causes the accumulation of sugars in the sieved elements generating a negative solute potential (quedas), with a drop in water potential (ψw), so water enters the sieved elements increasing the turgor pressure (ψp). With the discharge of phloem in the drain occurs lower concentration of sugars in the screened elements, increases the solute potential, becoming positive, thus the phloem water potential increases and thus the water leaves the conducting vessel. In the specific case of sugar movement in the phloem, it can be stated that this movement can occur both up and down in the plant.
The answer is <span>Meiosis I.</span>
<span>Meiosis is a cell division which results in the reduction of chromosome
number by half - from diploid to haploid - in daughter cells. It consists
of meiosis I and meiosis II. Meiosis I produces two
haploid cells. Meiosis
II is analogous to mitosis, so each of these two haploid cells will in meiosis
II produce two haploid cells. In total, meiosis results in four haploid cells.</span>
<span>
</span>
<span>Therefore, the production of two haploid daughter cells is in meiosis I.</span>
Evaporate.
I hope this helped you!
Question: Describe how a single amino acid substitution causes hemoglobin molecules to stick together. Use what you know about the structure of Hb and HbS, the properties of glutamic acid and valine, and how hydrophobicity causes molecules to behave in water.
Answer:
A Single amino acid must be polar to attract, just like water.
Explanation:
Sickle cell is an genetic illness and it is began by a alteration that arises in the beta sub units of the haemoglobin. Haemoglobin is a tetrameric protein made up of 2 alpha sub units and 2 beta sub units and it is the important part of the blood accountable for oxygen passage. Sickle cell is a illness that consequences from a replacement of a polar amino acid identified as glutamate with a non polar one valine at site six of the beta polypeptide component of haemoglobin. The replacement occurs as a consequence of a alteration in one of the bases in the beta-globin gene from adenine to thymine . As a outcome of this change, the beta polypeptide chains convert sticky in low oxygen circumstances since the valine sticks out of the chain and interrelates with neighboring non-polar amino acids.
