A single point mutation<span> can change the whole DNA sequence. Changing one purine or pyrimidine may change the amino acid that the nucleotides code for.</span>Point mutations<span> may arise from spontaneous </span>mutations<span> that </span>occur<span> during DNA replication.</span>
Answer: An enzyme is a biological catalyst that speeds chemical processes. A substrate is the substance that reacts in contact with an enzyme. Enzymes are specific when reacting with a substrate
Explanation:
Answer:
Amylase breaks: down starches and carbohydrates into sugars.
Protease breaks: down proteins into amino acids.
Explanation:
Photosynthetic bacteria are the main evidence of life in
early universe. These bacteria most likely produced oxygen, which was a waste
product that was caused by photosynthesis. As the oxygen levels increased, many
early forms of life were poisoned. This caused the evolution of new organisms
that were able to utilize oxygen for breathing or respiration.
Answer:
A pollen tube grows from the pollen grain into the ovary
Explanation:
Water is needed for fertilization in several plant groups because the sperm needs to swim to meet the non-motile eggs of the female organs.
<em>However in angiosperms, the pollen germinates and a structure known as pollen tube which contains the male gametophyte (sperm) grows into the ovary where the ovule is located and the male gametophyte is deposited in the ovule to initiate the fertilization process.</em>
<em>Hence, water is really not necessary for fertilization in the angiosperms.</em>
