IB Biology SL - Gas Exchange

6.4 Gas Exchange

6.4.1 Distinguish between ventilation, gas exchange and cell respiration

Ventilation: muscle movement to move fresh air into alveoli
Gas exchange: replacing carbon dioxide with oxygen in blood in lungs

Cell respiration: cellular energy production from glucose

6.4.2 Explain the need for a ventilation system

most cellular respiration is aerobic/requires oxygen / produces carbon dioxide;

they have thin walls with less elastic tissue/muscle/wider lumen;

ventilation system exchanges gases between inhaled air and lungs/blood stream;

ventilation system maintains high concentration gradient of gases in alveoli/ lungs

6.4.3 Describe the features of alveoli that adapt them to gas exchange.

Large total surface area à efficient gas exchange

Wall of single layer of flattened cells à short diffusion distance allowing rapid gas exchange

Moist lining à for the gases to diffuse into the blood before absorbed and to prevent the walls of the alveoli from sticking together

Walls elastic à

Network of capillaries à Have a low oxygen and high carbon dioxide concentration, allowing oxygen to diffuse into the blood and carbon dioxide to diffuse out of the blood

Capillary walls are thin/one cell thick

6.4.4 Draw and label a diagram of the ventilation system, including trachea, lungs, bronchi, bronchioles and alveoli.

                         

6.4.5 Explain the mechanism of ventilation of the lungs in terms of volume and pressure changes caused by the internal and external intercostal muscles, the diaphragm and abdominal muscles.

external intercostal muscles contract;

internal intercostal muscles relax;

pulling the rib cage upwards;

diaphragm contracts and flattens;

increase in volume of thoracic cavity;

this reduces pressure;

so air enters the lungs;

Meeting Deadlines - Time Management

 Managing your deadlines 

Making the most of the time students have enables students to be as efficient and successful as possible, leading a balanced life of work and play.

In order to meet assignment deadlines and to keep up with the schedules related to school and schoolwork, students must engage their temporal sequential ordering abilities.

For students with weak time management skills, procrastination can have painful consequences, affecting both academic and personal success.

Here are some strategies to help you to meet deadlines and adhere to school schedules:

• Create long term schedules to budget time (such as when managing a schedule of work and recreation or planning the timeline of a school project)

• efficiently stage or break down long term activities ( history report may be broken down into following stages Monday: Go to the library to collect sources Tuesday: Write first draft Wednesday: Proofread Thursday: Revise to final copy Friday: Take to school and submit)

• Prepare a written schedule of daily and weekly deadlines (reminders of tests and important long term projects) 

• make checklists - keep track of multi-step assignments and activities

• make personal schedules for study time, after school activities ( help students learn to set goals that emphasise important tasks they need to accomplish) 

Math Anxiety

Don't panic! Feeling nervous about math is very common. Do you ...

• feel NERVOUS before a math test? 
• PANIC and freeze while taking math tests?
• feel HELPLESS doing your homework?
• think that it's HOPELESS- you just fon't get math, never will, so there's no sense even trying?

NERVOUS NIGHTS

Stomach-churning head-spinning sleepless nights can be a sign of math anxiety. Try these simple ideas to help you relax and wake up feeling in charge.

1. Study- OK, that sounds obvious. Of course you should study. But look at #2...

2. Don't study too much! Spending too much time going over and over the same stuff won't help and will just overwhelm you.

3. Calm- those fears by treating yourself with calmness. Try to have a set routine- Go to bed on time. In the morning, eat breakfast, put on your lucky sweater (it works for me!), and pack yourself a treat for lunch. 

Test... Brain...Freeze...Panic

OK- you studied, got a good nights sleep and are wearing the lucky sweater. You get to class and forget your name. 

What to do now?

1. Remember your name? No, really - just think of something you DO know is the first step in remembering all those lost formulas.

2. Unfreeze your mind by unfreezing your body. Give yourself a quick stretch and tell yourself to be confident. Take a deep breath can break the cycle of panic.

3. Work around the panic by finding something on the test that you can do. Gain confidence and then go back and finish the rest of the problems. Keep going on the ones you can do, then go back and try the others. You might be surprised to find that you can now tackle them with ease. 

Math anxiety can be overcome. It is a matter of admitting that it is something you want to get over and working on it. 

Contributed by Jessica To

Math Tricks!

Multiply Up to 20X20 In Your Head

In just FIVE minutes you should learn to quickly multiply up to 20X20 in your head. With this trick, you will be able to multiply any two numbers from 11 to 19 in your head quickly, without the use of a calculator.

Try this:

• Take 15 x 13 as an example.
• First add 15+3 = 18
• Add a zero behind it (multiply by 10) to get 180.
• Multiply the covered lower 3 x the single digit above it the "5" (3 x 5 = 15)
• Add 180 + 15 = 195

That is it! Wasn't it easy? Practice it on paper first! 

Jessica To

Great Exam Stationary!

While I was writing this post, I realized that having good exam stationary really makes a difference in your exam performance, especially in essay based papers where you often find your hands to be numb from exhaustion afterwards. So here are some pens that I've tried and would like to recommend for all you exam takers out there:

Pilot G2 Gel Pen

This pen has a great grip and writes super smoothly to ensure both comfort and speed when you're writing an essay. Since it's gel, it also gives the nice, formal "look" of ink but doesn't smudge easily.

Progrex Mechanical Pencil

This pen is mechanical pencil has a steady grip and is environmentally friendly and is therefore great to have handy for diagrams and annotations and whatnot.

Papermate Kilometrico Ballpoint Pen

This is a personal favorite of mine for doing math or science papers that don't require such "extravagant" presentation as essay papers. The fine point writes smoothly but also makes your writing look tidy at the same time.

Uni Jetstream 101
This ballpoint pen is great for both math and science long answer papers, as well as essay papers for people who don't like using gel or ink. It writes smoothly and provides a nice grip and the colors are also very nice and dark, which is great for essay writing.

Useful English Vocab for Essay Writing

Here is a list of useful vocabularies recommended for you to use in your essay:

Useful verbs

• convey
• portray
• illustrate
• depict
• connote
• denote
• reveal
• show
• demonstrate
• establish
• indicate 
• craft
• suggest
• express
• describe
• insinuate
• imply
• symbolize

Useful Connectives

• However
• Similarly
• On one hand
• On the other hand
• Whereas
• On the contrary
• In contrast

Useful Discourse Markers

• Firstly
• Secondly
• Thirdly
• Lastly
• Furthermore
• Additionally
• In addition
• Although
• Therefore
• Consequently
• As a result
• Accordingly
• For this reason
• Given that
• Equally

Exam Tips!!

Doing well in an exam isn't just about studying, it's also about how you perform at an exam. One could have spent months reading and compiling notes in preparation for an exam, only to not do as well as one could have because they aren't well prepared to actually take the exam. Here are some tips:

• Be confident, but not overconfident: I always tell my friends that "stress is an exam killer", because it's really easy to get distracted and forget important information when you feel like you're under pressure. Therefore, I think the main thing that you really need to do before an exam is to believe in yourself. Don't panic about all the things that could go wrong, but instead tell yourself that you're already as well prepared as you could be and that you'll do just fine. However, don't be overconfident and just not study or not check your answers at the end of the exam. Overconfidence can be just as detrimental to your exam performance as stress, as it could lead to carelessness, which, believe it or not, could lose you a lot of marks in a paper, especially for subjects like math and science!
• Dress for the occasion: This may sound really stupid, but I actually spend ages picking out an outfit before an exam. When I tell my friends this, they always look at me like I'm crazy and ask me "why on Earth would you waste time doing that when you could be studying?". Good question. I believe that what you wear could greatly affect your morale under stressful situations such as exams. Though obviously wearing the right outfit won't magically get you that level 7 if you don't study, it does help you feel more comfortable and confident, which could really help you think more clearly and therefore perform better. A sweater paired with trackpants or leggings (for girls) are very popular choices for exam outfits, simply because they're comfortable. It's also important to dress for all sorts of temperature situations that the exam hall would throw at you. In an exam where you're tight in time, you wouldn't want to waste your precious seconds putting on or taking off layers of clothing. Therefore, if you opt for layers, wear a jacket or zipped hoodie instead of pullovers so they're easy to put on or take off. Of course, the ideal situation would be if you wore an outfit that wouldn't make you too warm or too cold, such as a long sleeve top or a shirt with a cardigan, so you would be comfortable throughout the whole exam and won't get distracted by the temperature!
• Prepare enough stationary: We all know that you can't write an exam without proper stationary. Therefore, remember to prepare enough stationary for every possible situation. It is better to be over-prepared and have a ruler at your English exam than to be without one during your math exam. Have a few of each type of pen, in case one runs out of ink, and line all your stationary up in front of you while you're waiting for the exam to start so you could have easy access to them when you need to. Make sure things like lead pencils are full and that your pens write smoothly. You can check out this post for some good exam stationary that we recommend.
• Don't try to study right before the exam: Though it may be tempting to try and cram until the last minute in order to ensure that you're as prepared as possible, it is also very unhelpful and creates unnecessary stress. Instead of trying to read your textbooks or your notes, take a few deep breaths, grab a drink or some snacks (but remember to go to the bathroom before you go in), and just relax to get yourself into the "zone" for the exam.
• Sleep!!!: I cannot stress this enough, but sleep is uber important when it comes to exams. Not getting enough sleep could lead to "brain freeze" situations, which is obviously not desirable when one is in an exam. So instead of trying to cram up to the last few minutes before going into the hall, get a decent 6-8 hours of sleep the night before instead to ensure that you maximize your performance.