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OCR Biology AS F211 May 2012

Feel free to try these:

1. Suggest two ways cell division in plants differs from cell division in animals. - 2 marks
2. Suggest two routes water molecules can take through the cell surface membrane. - 2 marks
3. Name 2 safety precautions that should be taken before using a spirometer. - 2 marks
4. Name the maximum resolution for a light microscope and for an electron microscope. - 2 marks

2. Suggest two routes water molecules can take through the cell surface membrane. - 2 marks

Through channel proteins in facilitated diffusion
Across carrier proteins in active transport

Is that correct?

Reply 221

sumsum123

2

Original post by Axion

We don't need to know about this :happy2:

Oh nice

Reply 222

Axion

15

Describe the structure of the SER (1 mark)

Reply 223

Unsworth

14

Original post by Axion

2. Suggest two routes water molecules can take through the cell surface membrane. - 2 marks

Through channel proteins in facilitated diffusion
Across carrier proteins in active transport

Is that correct?

I think that would get one mark. Water is never part of active transport to my understanding.

The mark would be 1. through channel proteins and 2. water can simply move across the membrane by osmosis as it is permeable to water.

Reply 224

sumsum123

2

Original post by Axion

In plant it forms cell plates. in animal cells two new cells are formed

Yup in plant cells you get a cell plate where the spindle equator was and then new cell membrane . And in animal cytokinesis starts from the outside. What would a deep s wave in an ecg suggest?

Reply 225

mathsclown

7

Original post by sumsum123

Yup in plant cells you get a cell plate where the spindle equator was and then new cell membrane . And in animal cytokinesis starts from the outside. What would a deep s wave in an ecg suggest?

Enlargement of the ventricular walls

Reply 226

Unsworth

14

Original post by mathsclown

200nm
0.2nm

1. you were correct.
2. Correct, but aquapotins? not ever heard of that ahah, channel proteins yes.
3. First answer no, second yes third yes. could also say check for medical conditions first i.e asthmatics.
4. correct!

Reply 227

mathsclown

7

Original post by Unsworth

1. you were correct.
2. Correct, but aquapotins? not ever heard of that ahah, channel proteins yes.
3. First answer no, second yes third yes. could also say check for medical conditions first i.e asthmatics.
4. correct!

Aquaporins sorry lol, thanks :smile:

Reply 228

PrettyLittleLiars

I got some questions:

1.What is the role of the cytoskeleton in cells? (3 marks)
2. How does water move up the xylem (4 marls)
3. how does meiosis differ from mitosis (2 marks)

Reply 229

PrettyLittleLiars

BTW can someone please explain spirometer to me. I just don't seem to understand it.

Reply 230

arvin_infinity

3

...The student then viewed cells from a different part of the onion root.
Suggest why all of the nuclei seen in this part of the root were in interphase.

?

Reply 231

PrettyLittleLiars

Original post by Axion

Huh? No it cant? The phospholipid bilayer is impermeable to water, only allowing lipid soluble substances through and denying entry to water soluble substances?

surely there is only one way which was the first i said?

Actually the phospholipid bilayer is partially permeable to both water and lipid based molecules. So water is able to directly diffuse through the bilayer.

Reply 232

Axion

15

Original post by PrettyLittleLiars

Actually the phospholipid bilayer is partially permeable to both water and lipid based molecules. So water is able to directly diffuse through the bilayer.

woooooops just read through my notes :lol:

will delete last post

Reply 233

TaraBelle

10

Original post by PrettyLittleLiars

Actually the phospholipid bilayer is partially permeable to both water and lipid based molecules. So water is able to directly diffuse through the bilayer.

isn't is those that are very small can pass through? ie water?

also guys what percent is this exam of the whole AS?

Reply 234

The Illuminati

4

Water molecules are small enough to pass through the membrane by osmosis. They can also pass through aquaporins.

Reply 235

The Illuminati

4

Original post by TaraBelle

isn't is those that are very small can pass through? ie water?

also guys what percent is this exam of the whole AS?

30% of AS

Reply 236

Unsworth

14

Original post by TaraBelle

isn't is those that are very small can pass through? ie water?

also guys what percent is this exam of the whole AS?

30%

Reply 237

sumsum123

2

Original post by mathsclown

Enlargement of the ventricular walls

Correct

Define homologous chromosomes.

Reply 238

Student-Andrew

12

Original post by PrettyLittleLiars

BTW can someone please explain spirometer to me. I just don't seem to understand it.

A spirometer consist of a chamber filled with oxygen that floats on a tank of water. A person breaths from a disposable mouthpeice attached to a tube connected to the chamber of oxygen (medically graded). Breathing in takes oxygen away from the tank causing the lid of the tank to move down. Breathing out forces air into the tank causing it to move up.

The movements are recorded on a data logger so a trace can be made

This is like the procedure of how a Spirometer works, sorry if it still seems like jargon

Reply 239

skylight17

2

Original post by arvin_infinity

...The student then viewed cells from a different part of the onion root.
Suggest why all of the nuclei seen in this part of the root were in interphase.

?

Most of the cell cycle is spent in interphase - this is where DNA replication and cell growth takes place before it begins division.

(edited 11 years ago)

OCR Biology AS F211 May 2012

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