Which of the following is a true statements about viruses?

Where are chromosomes found in the body cells

Monica [59]

Chromosomes are found in the nucleus of body cells. These chromosomes are made of protein and deoxyribose, which is a five-carbon sugar. Some of these chromosomes can be found in the mitochondria of a cell also. Hope this helps!

3 0

3 years ago

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What form a spindle shaped structure of protein fibres on which the chromosomes move during nuclear division?

frez [133]

Function of centrioles

An organelle that forms a spindle-shaped structure of protein fibers on which the chromosomes move during nuclear division are called the centrioles. Centrioles are part of the animal cell organelles. Hence, they are a small part of the microtubules organized and set in a particular course. Microtubules include 9 sets. Centrioles contain a cylindrical structure, packed with protein which is described as tubulin. Found mostly in eukaryotic cells beside the nucleus.

5 0

3 years ago

18. Refer to Models 1 and 2 to complete the chart below. Write yes or no in the box for cach cell.

Ostrovityanka [42]

The most primitive cells are prokaryotic. They are simple, with no organelles and no nucleus. Animal and plant cells are eukaryotic, but they express some differences such as the cell wall, chloroplasts, or centrioles.

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BACTERIA CELLS

Bacteria are prokaryotic cells.

Prokaryotic cells lack a nucleus, nucleolus, and organelles.

They only present plasmids, ribosomes, and genetic material in their cytoplasm.

DNA not surrounded by membrane

They have a cell wall that protects the cell and a cell membrane that surrounds the cytoplasm. Some of them can also present a capsule.

Some of them have flagellum.

These organisms are capable of inhabiting places with extreme temperature, salinity, acidity, or pH, among others.

ANIMAL AND PLANT CELLS

Both the animal and plant cells are eukaryotic.

They carry their genetic material in the nucleus and mitochondria.

Organelles are located in the cytosol, and both of them are surrounded by a protector cell membrane.

However, they have some differences:

⇒Cell wall : A rigid structure that provides support and protection.

• Animal cells do not have a cell wall. They are only surrounded by the cell membrane, which is flexible so they can adopt different shapes.

• Plant cells have a wall, so their shape is usually prismatic and regular. The cell wall is composed mainly of cellulose.

⇒ Chloroplast: these are organelles that accumulate chlorophyll.

• Animal cells do not have chloroplasts because they do not photosynthesize.

• Plant cells have chloroplasts, and they are in charge of the photosynthesis process that allows plants to release oxygen. These organelles use solar light as the source of energy.

⇒ Vacuoles:

• Animal cells have many and small vacuoles whose function is to store water, ions, and waste intracellular substances.

• Plant cells have a unique big-sized vacuole that might occupy almost 90% of the cell. Their principal function is to store water and keep the turgidity. When the vacuole gets empty, the plant loses rigidity.

⇒ Other differences are: