Answer:
Sometimes molecules cannot move through the cell membrane on their own. These molecules need special transport proteins to help them move across the membrane. Facilitated diffusion is the diffusion of substances with the help of transport proteins in the plasma membrane. These special proteins are called channel proteins or carrier proteins, and they are attached to the cell membrane. In fact, they go through the cell membrane, from the inside of the cell to the outside. Facilitated diffusion is used for molecules that cannot diffuse rapidly through cell membranes on their own, even when the molecules are moving from high to low concentration areas. An example is the sugar plants and animals use for energy, called glucose. Even though facilitated diffusion involves transport proteins, it is still passive transport because the solute is moving down the concentration gradient so it does not require the use of cellular energy.
Answer:
3 long tails : 1 short tail
Explanation:
This question involves a single gene coding for tail length in mice. The allele for long tail (T) is dominant over the allele for short tail (t). This means that an heterozygous mice will possess the long tail length.
According to this question, in a cross between two hybrid or heterozygote mice i.e. Tt × Tt, the following gametes will be produced by each parent:
Tt - T and t
Using these gametes in a punnet square (see attached image), the following will be produced: TT, Tt, Tt and tt.
Offsprings with genotype TT, Tt and Tt will have a LONG TAIL while genotype tt will have a SHORT TAIL. Hence, the phenotypic ratio will be 3 long tails : 1 short tail.
Well firstly, alleles are different versions of genes. A dominant allele will show it's trait regardless of if the organism only has one copy of the allele (heterozygous). A recessive allele will show the effect only if two copies of the allele are present (homozygous)
Answer:
DNA is the information molecule. It stores instructions for making other large molecules, called proteins. These instructions are stored inside each of your cells, distributed among long structures called chromosomes. These chromosomes are made up of thousands of shorter segments of DNA, called genes.
Explanation:
Answer:
Carbohydrates and lipids are similar in that they are both sources of energy but they are different in the amount of energy they produce.
Explanation:
Carbohydrate and lipids are similar in the sense that both of them are parts of foods consumed by humans and the two marcro molecules are good sources of energy for the body cells. The carbohydrate has to be broken down to glucose before it can be absorbed by the body cells. This is because glucose is the only energy source that the body cells can use. The lipid has to be converted to glucose through biochemical reactions such as gluconeogenesis before the cells can use it.
The basic difference between the two energy sources is that the amount of energy that they supply is quite different. Lipid contains more energy than carbohydrate; carbohydrate can only supply about one-quarter of the energy that lipid can supply.
