If a cell has 8 chromosomes at the beginning of mitosis, how many

<span>(1) Specific sections of DNA molecules in the
chromosomes are activated.</span> This <span>contain identical chromosomes to function
differently.</span>

7 0

3 years ago

1. Suppose the synthesis of an amino acid was accomplished by four enzymes encoded by four genes that formed an operon. Draw a m

vivado [14]

I have attached lac operon model having 4 genes. See attachment for better understanding.

Answer:

The Lac operon is controlled by two signals.

Initiation

Glucose and lactose concentrations control the initiation of transcription of the Lac operon through their effects on the Lac repressor protein and Cap.

Lactose absent (Repression)

When lactose is absent, the Lac repressor binds the Lac operator and shuts off expression of the operon.

Lactose present (Transcription)

Addition of lactose increases the intracellular concentration of a related compound, allolactose. allolactose binds to the Lac repressor, causing it to undergo a conformational change that releases its grip on the operator DNa.

Glucose absent (Repression)

When glucose is absent, cyclic aMp (red triangle) is produced by the cell and Cap binds to DNA.

Glucose present (Transcription)

LacZ, the first gene of the operon, encodes the enzyme b-galactosidase, which breaks down lactose to galactose and glucose.

7 0

3 years ago

What are two major advantages of high-yield modern agriculture? what are the major harmful environmental impacts of agriculture?

goldfiish [28.3K]

1.High yield modern agriculture refers to the practice of breeding genetically modified crops or using fertilizer to increase the production yield of planted crops. Two advantage of high yield modern agriculture are:
1. Production of large quantities of planted crops.
2. Ability to select and breed plants with superior qualities.

2. Agriculture have some negative influence on the environment, the major harmful environmental impacts of agriculture are:
a. Habitat loss: Agricultural practices present great danger to species and ecosystem. This is because, farmed areas serve as habitats for different types of wild plants and animals. Farming the areas makes these living organisms to lose their habitats and these throw the ecosystem into imbalance.
b. Soil erosion and degradation: When natural vegetation are converted into agricultural lands, the breaking up of the soil leads to erosion, which wash away the top soil and the nutrients that are embedded in it.
c. Pollution: The chemicals that are used during farming operations, such as fertilizers, pesticides, etc. cause pollution of the air and the surrounding waters.
3. Soil erosion is the process by which the top layers of soils are carried away by agents such as wind and water. The biggest negative effect of soil erosion is the loss of top soil. The top soil is the part of the soil that contain most of the nutrients that plants use to grow. When this part of the soil is lost, the soil usually becomes non fertile. Soil erosion can also lead to water pollution. When soils are eroded from the farm lands and carried to the surrounding waters, the waters will be polluted by the chemicals such as pesticides, herbicides and fertilizers, which are had been used on the soils. This can lead to the death of the animals that are living in the waters.

4 0

3 years ago

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