Answer:
3. the absence of a cell wall in human cells
Explanation:
Animal cells do not have cell walls. Cell membranes separate the cytoplasm of the animal cells from the surroundings and maintain their interior. Plant cells have cellulosic cell walls. A cell wall surrounds the cell membrane of a plant cell. Cell walls serve to provide structural support and protect plant cells from pathogens. Cell walls also help keep excess water out of cells so they do not burst. Therefore, human cheek cells would not have cell walls while the onion cells would have cell walls made up of cellulose.
Mitochondrial DNA can be traced for generations. It is because of the fact that unlike nuclear DNA, mitochondrial DNA rarely gets mutated. The frequency of mutations in the mitochondrial DNA is approximately one every 3,500 years per nucleotide. That is why mitochondrial DNA of a person is almost similar to his/her direct maternal ancestor. So, it can be used to match lineages amongst people.
To know what type of transport occurred the lab and collected data are needed. As they are not present an explanation of the different transport's types, will be given.
Water, proteins, ions, and molecules of different sizes can pass through the cell membrane using different types of transports. The transport that each molecule uses depends on the concentration, size, and polarity.
We can classify the types of transport as active and passive.
Passive transport is the one that does not need energy to happen since the molecules move from a place of high concentration to a one of lower concentration. In this group, we have:
- Simple diffusion: small molecules in high concentration on one side of the membrane; move to the other side due to the difference in concentration.
- Osmosis: water passes through the membrane from a place of low concentration of molecules to one of high concentration. Water moves inside or outside the cell to valance the concentration of solutes on both sides of the membrane.
- Facilitated diffusion: uses proteins to transport large molecules, ions, or hydrophobic molecules from one side to the other. In this type of transport, we have proteins that form channels so those hydrophobic molecules can pass through the lipid membrane, and carrier proteins, which binds to a specific molecule changing their shape and transporting the molecule.
Active transport needs the<em> energy</em> to transport molecules; since it goes against the gradient's concentration. In this group, we have:
- Sodium-Potassium pump: uses ATP to move sodium outside the cell and potassium to the inside. The ions with this transport go to where they are most concentrated.
In conclusion, there are different types of transport; they depend on the concentration or type of molecule. To find out what mechanism of transport occurred in the lab, look at the components of the experiment and analyze which of these transports could be present.
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Fibroblasts, cells found in the connective tissues of the body, make up the hypodermis. These produce collagen proteins, which aid in preserving the body's structural foundation.
- The body's bottom layer of skin is called the hypodermis. It serves a variety of crucial roles, including energy storage, tying the muscles and bones beneath the skin's dermis layer to one another, keeping the body warm in a variety of temperatures, and guarding against injury-related harm.
- The hypodermis shrinks with ageing, the skin begins to sag, and the skin is more susceptible to damage and injury.
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Photosynthesis makes the glucose that is used in cellular respiration to make ATP. The glucose is then turned back into carbon dioxide, which is used in photosynthesis. While water is broken down to form oxygen during photosynthesis, in cellular respiration oxygen is combined with hydrogen to form water.
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