Answer:
B) Two different species of bacteria can share DNA, including antibiotic-resistance genes, during conjugation.
Explanation:
Conjugation is a process by which bacteria can exchange their genetic material between them. So through conjugation, the antibiotic-resistant gene coded by plasmid can be transferred through sex pilus to another bacteria.
So due to conjugation two different species of bacteria can share DNA which can include antibiotic-resistant genes. Therefore, through conjugation genetic variation and evolution are favored in bacteria. So due to this reason conjugation is a very important process in bacteria to spread antibiotic-resistant genes.
Answer:
D. A mutation causing uncontrolled cell division
Explanation:
Cell division is controlled by various mechanisms. Any mutations in the genes regulating the cell division lead to uncontrolled cell division. Loss of control over the process of cell division leads to the formation of tumors.
These tumors may cause cancer if they are transformed into malignant tumors. Hence, a mutation that causes loss of control over cell division is harmful.
Answer:
b. a semi-permeable double layer of phospholipids that have hydrophilic heads and hydrophobic tails
Explanation:
B is correct as the cell membrane is selectively semi-permeable. It is selectively semi-permeable because this quality allows it to control what can and can't enter the cell, and how it does so.
The cell membrane also has a phospholipid bi-layer comprised of a double layer of phospholipids which have hydrophilic head and hydrophobic tails. This is because the heads are made of phosphate and are polar and are therefore attracted to water (hydrophilic), while the tails are made of lipids (i.e. fats, oils) which do not mix with water and are therefore hydrophobic.
The properties of each phospholipid is also why they form the double layer structure, the hydrophilic heads naturally face outwards into the water and protect the hydrophobic tails on the inside.
Hope this helped!
Answer:
Quartzite is formed from the metamorphism of sand stone
