OCR Biology Revision Thread - 8th June Exam

here is a summary of smoking:

cigarettes contain the following:

Tar
nicotine
carbon monoxide

Nicotine - addictive substance in cigarettes

nicotine mimics the transmitter substance in the synapse of nerve cells. This makes the nervous system more sensitive and the smoker becomes more alert

nicotine causes the release of the hormone adrenaline. This causes an increase in the heart rate, breathing rate and causes the constriction of the arterioles. This raises the blood pressure

nicotine makes platelets sticky. This increases the risk of a blood clot of thrombus occurring

Carbon monoxide - carbon monoxide enters the red blood cells and combines with oxygen to form carboxyhaemoglobin which has a lower affinity for oxygen. This reduces the oxygen carrying capacity of the blood. The heart may detect this and increase heart rate.

also carbon monoxide damages the lining of the arteries.

Tar: -

rest of tar stuff is in book.

Reply 4

collagen:

fibrous protein
consists of amino acid subunits
amino acids are held together by peptide bonds
consists of three plolypeptide chains held tightly and twisted around each other to form a triple helix
insoluble in water
cross links ( covalent) act between collagen.
strong so it used to form connective tissue and cartilage and used in bone
also used to provide mechanical strenght to the walls of arteries to prevent bursting.
minerals can bind to triple helix which increased righidity.

Reply 5

Kalliope

YAY!! I'm doing that one :smile:

Soo worried lol!

EDIT: Hang on - oops! I'm doing the AQA 45 minute one in the morning of the 8th of June, not this one! :smile:

Reply 6

starch:

polysacharide
consists of alpha glucose subnits
held together by 1.4 - glycosidic bonds
consists of amylopectin which is long branched chains of alpha glucose.
consists of amylose which is unbranched.
compact molecule as amylopectin is coiled. Therefore more can be stored in a small space
insoluble in water so it doesn't affect water potential of cells
used in energy storage so these features are ideal
also because amylopectin is branched enzymes can break down the glycosidic bonds easily so glucose can be hydrolysed quickly.

Reply 7

HotCoco.

I'm supposed to be resitting this and only started revision this week. :awesome:

Reply 8

HumanNature1992

I think smoking will deffo come up, they completley ignored it in Jan, so WATCH OUT! :eek3:

Reply 9

Narik

Ugh. I'm so going to flop - I just can't face having to learn how to count daisies. :facepalm2:

Reply 10

haemoglobin:

consists of 4 polypeptide chains two are alpha and two and beta
globular protein
soluble in water as hydrophilic R groups face outwards and hydrophobic R groups face inwards. Good for transport in blood
involved in carrying oxygen from lungs to tissues
consists of 4 haem groups which can bind to oxygen.

Reply 11

are these summaries helping?

Reply 12

Shortyyyy

I have the exam but in the afternoon because I have my sociology exam in the morning. arghhhhh i feel sorry for my hands :frown:

Reply 13

HumanNature1992

TX22

here is a summary of smoking:

cigarettes contain the following:

Tar
nicotine
carbon monoxide

Nicotine - addictive substance in cigarettes

nicotine mimics the transmitter substance in the synapse of nerve cells. This makes the nervous system more sensitive and the smoker becomes more alert

nicotine causes the release of the hormone adrenaline. This causes an increase in the heart rate, breathing rate and causes the constriction of the arterioles. This raises the blood pressure

nicotine makes platelets sticky. This increases the risk of a blood clot of thrombus occurring

Carbon monoxide - carbon monoxide enters the red blood cells and combines with oxygen to form carboxyhaemoglobin which has a lower affinity for oxygen. This reduces the oxygen carrying capacity of the blood. The heart may detect this and increase heart rate.

also carbon monoxide damages the lining of the arteries.

Tar: -

rest of tar stuff is in book.

The more important stuff for smoking is in terms of diseases, like atherosclerosis, CHD, stroke, lung cancer, Chronic Bronchitits and Emphysema. :confused:

Reply 14

Jono300

OP

4

HumanNature1992

I think smoking will deffo come up, they completley ignored it in Jan, so WATCH OUT! :eek3:

But they also included a large 7 mark question on emphysema last June. So, if smoking does come up, it will probably be short-answer questions.

Reply 15

HotCoco.

Since this is a new syllabus, they will want to test the new aspects of the course. Things like the environment stuff will come up plenty I imagine.

Reply 16

HotCoco.

HumanNature1992

The more important stuff for smoking is in terms of diseases, like atherosclerosis, CHD, stroke, lung cancer, Chronic Bronchitits and Emphysema. :confused:

Yep.

Reply 17

God Help Me

2

I'm Doing it !!! :woo
Too busy revising for C2 right now though cuz I flopped stupid M1 !

Reply 18

HumanNature1992

Jono300

But they also included a large 7 mark question on emphysema last June. So, if smoking does come up, it will probably be short-answer questions.

I dunno, Its quite an easy topic, just theory. If they do happen to ask another big mark question then its quite easy to get the marks. I can see a big mark question on the effects of smoking on the cardio vascualar system, since they only asked it on the gas exchange system (emphysema) in june (I sat the exam :P)

Reply 19