A few Biology questions! In need of assistance b4 2moro's exam! (1 Viewer)

[x.Exhaust.x]

I need all the help I can get with the following questions. Exams begin tomorrow! Gah, I don't feel well about this. Must maintain top 5 ranking. STRESS STRESS STRESS.

1. List one site of mitosis in flowering plants and one site of mitosis in adult mammals, and in each case explain why mitosis would occur here.

2. Explain how radioisotopes could be used to track the movement of the dye through the celery.

3. All mammals have a digestive system designed to digest food and absorb nutrients. Compare and contrast the digestive systems ofa carnivorous mammal, a herbivorous mammal and a nectar-feeding mammal, relating the differences between these systems to the animals' diet.

4. Use the concept of surface area to volume to explain:

(a) Why cells are microscopic.

(b) How plants increase their absorption of water.

With Life on Earth and Evolution of Australian Biota, what are the main significant dotpoints throughout the module? I know for Life on Earth, the Miller Urey Experiment is emphasised quite a lot in past papers. But I'm not sure about others.

Thanks.

 

[12o9]

I need all the help I can get with the following questions. Exams begin tomorrow! Gah, I don't feel well about this. Must maintain top 5 ranking. STRESS STRESS STRESS.

1. List one site of mitosis in flowering plants and one site of mitosis in adult mammals, and in each case explain why mitosis would occur here.

2. Explain how radioisotopes could be used to track the movement of the dye through the celery.

3. All mammals have a digestive system designed to digest food and absorb nutrients. Compare and contrast the digestive systems ofa carnivorous mammal, a herbivorous mammal and a nectar-feeding mammal, relating the differences between these systems to the animals' diet.

4. Use the concept of surface area to volume to explain:

(a) Why cells are microscopic.

(b) How plants increase their absorption of water.

With Life on Earth and Evolution of Australian Biota, what are the main significant dotpoints throughout the module? I know for Life on Earth, the Miller Urey Experiment is emphasised quite a lot in past papers. But I'm not sure about others.

Thanks.

3 Digestion in Herbivores
The food consumed by herbivores has a low nutrient value and contains a lot of fibrous matter which is difficult to digest. The fibre is mostly the play cell walls, made of cellulose. Animals lack the necessary digestive enzymes to break the cellulose down.Herbivores generally have:

• Flat grinding teeth to chew the food thoroughly to increase the surface area exposed to digestive enzymes
  
• Relatively long intestines and caecum, so that there is more surface area and longer time available for digestion
  
• Bacteria living in their gut, which have the enzymes to digest cellulose. This is an example of mutualism.

Digestion in Carnivores
Carnivores do not require huge digestive systems. Their food is much more concentrated in its nutritional value and relatively easy to digest.
Carnivores have:

• Sharp, tearing teeth to cut flesh into chunks for swallowing
  
• Relatively short intestines
  
• Highly elastic stomach which allows them to swallow a large meal. The stomach acid and enzymes are vital for digesting their high protein meat diet.

4a) To maintain a servicable SA:V ratio
The concept of diffusion and 'surface area to volume ratio' is similar to the way cells function. Like inanimate objects, the rate in which substances diffuse into cells is determined by their surface area to volume ratio. As the cell grows, its surface area to volume ratio decreases, to a point where diffusion will not able to provide it with enough nutrients to keep it alive. This is why cells are fairly small and cannot exceed a certain size. When the cell reaches its maximum capacity, it divides as to support diffusion.

b)In aquatic environments, water and minerals can be absorbed across the whole surface of the plan. In most terrestrial plants, water and minerals are obtained through the root systems. These roots need a large surface area to absorb nutrients for the whole plant. This is done through special outgrowth on the roots known as ‘root hairs’ Each root hair Is part of one, very elongated cell. Root hairs help absorption of water by greatly increasing the surface area of the root in contact with the soil.

 

[x.Exhaust.x]

Thank you 12o9! When I receive my result for bio, you would have contributed positively to it .

 

[12o9]

haha. it's cool . anyways.

1.
Mammals -Skin - replacing cells that continually die and fall off.
Plants - Tips of roots and stems - Growth

2.
Radioisotopes can be used as tracers due to their chemical similarity to their non-radioactive counterparts. Due to this similarity, the nuclides that emit radiation are treated without discrimination by the chemical, ecological and biological processes that an organism undertakes. As such, the isotope can be tracked by the radiation that it produces. Hence, if radioisotopes were added to the dye of the celery, it is possible to trace it's movement.

 

[x.Exhaust.x]

What about the digestive system of nectar-feeding mammals? I wish I didn't have a substitute and should've self taught myself. Sorry about bothering you 12o9. If you can't answer, it's fine, I'll do some research myself . Thanks again.

 

[12o9]

The diet, sugars/nectar, consumed by nectar feeders requires little digestion as sugars do not need to be broken down. Because of this, their digestive systems are generally very short and simple. Most nectar feeders also do not have teeth.

^that's all i remember from class =/ I accidentally skipped that part of the dotpoint x).

 

[omniscience]

What about the digestive system of nectar-feeding mammals? I wish I didn't have a substitute and should've self taught myself. Sorry about bothering you 12o9. If you can't answer, it's fine, I'll do some research myself . Thanks again.

1. Honey possum: Tarsipes rostratus
Honey possums are highly specialised to exploit the nectar and pollen of banksia inflorescences. The teeth are tiny and peg-like and there are fewer teeth than in other marsupials (no more than 11 on each side).
The jaw is reduced to a thin flexible rod. The jaw musculature is consequently much reduced. The head is tapered with a narrow snout. The tongue is long, slender and protrusible, and its end is brush-like. The finger-like projections of the tongue slope to the throat, facilitating the transport of nectar and pollen into the mouth. The stomach is large and two chambered; the second chamber may serve to store nectar. It also lacks any protein digesting enzyme. There is no caecum; pollen is digested progressively in the small intestine.

 

[x.Exhaust.x]

Thank you as well omniscience .

 

[bubblesss]

4. Use the concept of surface area to volume to explain:

(a) Why cells are microscopic.

(b) How plants increase their absorption of water.


a) as cells become larger their volume increases faster than their surface area. doubling the volume would double the metabolic reactions but the surface area only increases by a bit. thus the cell has difficulty taking in food and ejecting waste products. in other words only a microscopic cell would have a large enough surface area whereas the larger cell wouldn't survive.

b) plants increase their absorption of water with the help of root hairs. the roots spread in the soil thus increasing the surface area for absorption and allowing maximum intake of water and nutrients.