Why is crossing over of the chromosomes during meiosis important? (multiple choice)

To ensure that a human gene is translated properly in a bacterial cell, you should clone the _____________ for the gene instead

bekas [8.4K]

Answer:

complementary DNA (cDNA)

Explanation:

The complementary DNA (cDNA) is a region of DNA that is synthesized from an RNA template by using a reverse transcriptase enzyme. cDNA is usually used to clone genes from eukaryotic organisms in prokaryotes. cDNA cloning is a technique that consists of isolating and amplifying a self-replicating prokaryotic organism that includes in its genome a cDNA of interest. This technique enables the insertion of fragments of eukaryotic DNA (cDNA) into plasmids that subsequently are multiplied by cloning and finally sequenced.

7 0

3 years ago

Describe: how does desert plants carry out photosynthesis?

WINSTONCH [101]

During night, desert plants absorb carbon dioxide and form an intermediate. Then during day time when the stomata is closed to prevent loss of water, they use this stored carbon dioxide to perform photosynthesis.

3 0

3 years ago

¿por que es importante para el hombre que la milasa actué sobre el almidón? Ayuda porfa

loris [4]

Answer:

can you put this in English pls

8 0

3 years ago

1. Why does the moon go through Phases?

liq [111]

Explanation:

1.The Moon has phases because it orbits Earth, which causes the portion we see illuminated to change. The Moon takes 27.3 days to orbit Earth, but the lunar phase cycle (from new Moon to new Moon) is 29.5 days. The Moon spends the extra 2.2 days "catching up" because Earth travels about 45 million miles around the Sun during the time the Moon completes one orbit around Earth.

2.

An eclipse is the result of the total or partial masking of a celestial body by another along an observer's line of sight. Solar eclipses result from the Moon blocking the Sun relative to the Earth; thus Earth, Moon and Sun all lie on a line. Lunar eclipses work the same way in a different order: Moon, Earth and Sun all on a line. In this case the Earth's shadow hides the Moon from view.Lunar and solar eclipses occur with about equal frequency. Lunar eclipses are more widely visible because Earth casts a much larger shadow on the Moon during a lunar eclipse than the Moon casts on Earth during a solar eclipse. As a result, you are more likely to see a lunar eclipse than a solar eclipse.

3.Why Do We have Seasons?

As the earth spins on its axis, producing night and day, it also moves about the sun in an elliptical (elongated circle) orbit that requires about 365 1/4 days to complete. The earth's spin axis is tilted with respect to its orbital plane. This is what causes the seasons. When the earth's axis points towards the sun, it is summer for that hemisphere. When the earth's axis points away, winter can be expected. Since the tilt of the axis is 23 1/2 degrees, the North Pole never points directly at the Sun, but on the summer solstice it points as close as it can, and on the winter solstice as far as it can.

Why Do the Seasons Change on Earth?

Two things cause the seasons to change. First, the Earth moves around the Sun. Second, the Earth has a tilted axis of rotation.

The Earth spins around an axis. This imaginary line extends from the South Pole to the North Pole. But the Earth’s axis is not vertical. It’s actually tilted at an angle of 23.5°. The planet is always tilted in the same direction as it orbits the Sun.

4 0

3 years ago

A, B, C, D and E are pathogens of different diseases for human beings. The route of entry of pathogens in human body is differen

Goryan [66]

Answer:

Microorganisms which causes diseases is known as pathogen.

Explanation:

PATHOGEN -: Pathogens are agents that live in a host and are responsible for causing infections or diseases in that host, such as a human being. Microorganisms such as bacteria , viruses , fungi or protozoa, or other organisms such as parasites, worms and even contagious proteins such as prions, may be pathogens.

Viruses: Viruses are micro-organisms that are composed of nucleic acid and covered by a protein sheet. A lipid (fatty) outer layer is also present in some viruses. Enveloped viruses are called these. Non-enveloped viruses are considered those that do not have this lipid outer layer. Only inside their host's living cells are viruses able to replicate. EXAMPLE -: Influenza (influenza A and B viruses) and the common cold (rhinovirus) are examples of infections caused by viruses.

Bacteria: These are microorganisms which have a nucleus containing DNA surrounded by a cell wall or membrane. Among bacteria, the composition of the cell wall differs. If they are able to access food and nutrients, they have a more complex structure than viruses and can multiply beyond the host. EXAMPLE -: Foodborne diseases can be caused by bacteria such as Salmonella enterica and Escherichia coli, while Staphylococcus aureus can cause skin infections.

Fungi: Fungi are single-celled or multicelled species that can live outside a host. They consume food and nutrients created after digestive enzymes have been secreted into their atmosphere. example-:  The foot of the athlete (Trichophyton mentagrophytes) and yeast infections (Candida albicans) are examples of infections caused by fungi.

Prions: These are infectious agents made up entirely of proteins and capable of transferring to other prion proteins their infectious properties. EXAMPLE -: Extreme infectious diseases such as bovine spongiform encephalopathy (mad cow disease) and variant Creutzfeldt-Jakob disease (vCJD) can be caused by prions.

Protozoa: Protozoa are single-celled organisms that display habits that are similar to animals, such as the ability to travel through water, and are capable of harvesting other microorganisms. They are able to live outside the human host, but when they enter the human host and spread, causing infections and diseases, they may also be parasitic in nature.  EXAMPLE -: Malaria and giardia include common infections

Yes , pathogen enter into the body directly -: Direct contact infections spread when, through direct physical contact with blood or body fluids, disease-causing microorganisms move from the infected person to the healthy person. Touching, kissing, sexual contact, contact with oral secretions, or contact with bodily lesions are examples of direct contact.
INCUBATION PERIOD OF A PATHOGEN -:The period of incubation is the interval between exposure to a pathogenic organism, a drug, or radiation, and when the first signs and symptoms are evident.

5 0

3 years ago