There are 2 types of transport mechanisms that involve the movement of materials across the cellular membrane:
1. Passive Transport Mechanisms which is the movement of materials that does not require energy. Instead the movement relies on the permeability of the cell. Under this are three kinds of passive transport mechanisms:
a. Simple Diffusion:
- the movement of materials from a region of higher concentration to lower concentration. No external energy is necessary for the movement. The materials supply the energy themselves.
b. Facilitated Diffusion:
- This differs from simple diffusion because the movement is facilitated by proteins that make up the structure of the membrane. The proteins include channel proteins that allow ions and smaller molecules to cross the membrane. The other protein are the carrier proteins, which bind to materials like sugar molecules and move it across the membrane.
c. Osmosis:
- This is the diffusion of water across the membrane. Osmosis moves water from regions where there are more water molecules of water per volume to regions where there are less water molecules per volume.
2. Active transport on the other hand is a movement mechanism that requires energy. It uses the energy to send materials against the direction it is coming from through simple diffusion. This mechanism is used in a way to keep unwanted ions or other materials out of the cell.
Answer:
B
Explanation:
Nucleic acid digestion yields nucleotides, whereas protein digestion yields amino acids. Both digestive processes require the presence of Hydrochloric acid to lower the pH. Hydrochloric acid popularly described as HCl contributes in both protein and nucleic acid digestion by supplying hydrogen ions which in turn activate pepsinogen, which in turns form pepsin necessary for digestion.
They do not produce gametes so they cannot reproduce sexually. They need to reproduce asexually. There are numerous asexual reproduction types. Some include: binary fission and budding
Answer:
genotype is responsible for establishing phenotype
Explanation:
When Mendel experimented with pea plants, concept of genes and alleles had not come up yet. Through his experiments Mendel first proved that some type of combination in cells leads to a particular phenotype.
He coined the term "factors" which are today known as alleles. These factors paired up and displayed a particular phenotype. Today we know that the alleles are responsible for a genotype which ultimately results in a phenotype. Hence, he established that genotype is responsible for establishing phenotype even before the term genotype was coined.