1. The answer is; D
All cells that respire have to expire. This is a characteristic of all living things. Cells release their waste products through the process of exocytosis to maintain a homeostatic environment on their inside. The waste, if it’s damaged proteins, are first broken down by proteasomes before they are released out. An example is the fact that smelly feet are as a result of the waste product of bacteria after they’ve broken down the sweat on your feet. In the body, this waste by the cells is excreted from the system by the excretory organs such as kidney and skin.
2. The answer is; A
This is because bacteria break down large molecules to their constituent elements. An example is their important role in decomposition. Bacteria, such as chemotrophs, and autotrophs also help form molecules through anabolism. This is also why bacteria are hence important in biogeochemical cycles such as nitrogen and carbon cycles.
3. The answer is; C
Fungi and protists (unicellular eukaryotes) have nuclei. This means that their genetic material is surrounded by a nuclear membrane and demarcated from the rest of the cytoplasm. The virus, on the other hand, is a non-living entity and only depend on other cells machinery to replicate. Therefore cannot even carry out a process such as chemosynthesis.
4. The answer is; A
The biggest difference between angiosperms and gymnosperms is the fact that the seeds of gymnosperms have no seed coat. In addition, gymnosperms (such as conifers) do not produce flowers hence are referred to as non-flowering plants.
5. The answer is; D
Moss is a plant species in the bryophytes group of plants. These plants are embryophytes meaning they develop a multicellular embryo in a stage of their life cycle. These plants do not have a well developed vascular system (or lack one) which distinguishes them from vascular plants. Other plant species in the group are liverworts and hornworts. Their life cycle is dominated by the gametophyte phase.
6. The answer is; B
Its enzyme is well known for the breaking of glycosidic bonds of carbohydrates and other polysaccharides. Carbohydrate is its main source of energy. These bacteria are a part of the normal flora of the human gut and therefore assist in breaking down dietary carbohydrates. This bacteria is, however, an opportunistic bacteria and can cause infections when the immune system of the person is compromised.
7. The answer is;
This enzyme can bear low pH because it has a high negative surface charge that stabilizes them at low pH. Most enzymes become denatured in low or high pH because they denature. The pH changes the ionization of the amino acid residues in the protein and disrupts the interaction (such as hydrogen bonding) between the residues hence affects the folding of the protein.
8. The answer is; D
All plants generally reproduce in the same way. They differ in the dominant stages in their life cycle between species. Most higher plants have the sporophyte phase as their dominant cycle while the lower plants have the gametophyte as their dominant phase. Therefore limiting factors are similar for all the plants.
9. The answer is; D
Root hairs are numerous extensions on the root and are small (even microscopic) in size. This increases the surface to volume ration that the root is in contact with the soil. This maximizes the capacity of the root to absorb nutrients and water from the soil.
10. The answer is; A
The endosymbiotic theory postulates that mitochondria and plastids emanated from an endosymbiotic relationship between a protist cell and a prokaryotic cell that evolved over many years. Today, this evidence is in the fact that these organelles have their own DNA that replicates independently from that of the host cell. Another evidence is that these organelles also have double membranes.
11. The answer is; One scenario is that the plant would die;
and the second is that the plant would wilt
The stomata are critical in the transpirational pull of plants that ensures they maintain turgidity giving them support. This occurs when water is lost through the stomata and replaced by that absorbed by the roots and brought up through the xylem.
Carbon dioxide, that is critical in photosynthesis in plants also passes through the stomata. This means that the plant would be unable to make their own food.
12. The answer is; B
The exploding of puffballs exposes the numerous spores in the gills of the fungi. This also pushes the spores out into the environment and enables the wind and other agents of dispersal to disperse the spores further away from the mother plant. This ensures that the chances of survival of the fungi are higher because this dispersal increases the chances that the spores will find a suitable environment to grow.
