revision: Biology - Topic 1

Cells and Respiration-

CELLS-
1. Describe cell structures including the nucleus, cytoplasm, cell membrane, cell wall, chloroplasts and vacuole.
Describe the functions.

-Nucleus = Where all the genetic information of the cell is kept (DNA).
-Cytoplasm = The gel-like substance where most of the chemical processes that occur in the cell happen.
-Cell Membrane = It controls what enters and leaves the cells as well as surrounds the cell for protection and support.
-Cell Wall = It prevents over-expansion of plant cells when water enters. and provides protection as plants do not have a skeleton.
-Vacuole = Filled with water and found only in plant cells, it controls and maintains the substances within the cells and gets rids of waste products.
-Chloroplasts = The green color of the plant that captures light energy needed to conduct photosynthesis.

2. Movement of substances into and out of cells.
Diffusion = The movement of particles from an area of lower concentration to an area of higher concentration.
Osmosis = The movement of water through a semi-permeable membrane to balance out the concentration.
Active transport = The movement of particles against the concentration and requires energy. (eg. minerals up root hair cells)

Answering the question->
A: State where the high concentration is, and where the low concentration is. Therefore there is a concentration gradient.
B: "Water moves along it's concentration gradient."
-State direction -> down concentration gradient or against concentration gradient.
-Name the process -> diffusion, active transport, osmosis.
(DO NOT USE ISOTONIC, HYPERTONIC or HYPOTONIC TO ANSWER THESE QUESTIONS, IT WILL CONFUSE YOU OVER WHICH IS WHICH.)

REMEMBER -> Hypertonic = more concentration. I am hyper cuz I got more sugar xD

 Passive means no energy which is what osmosis and diffusion is.

Plants with turgid cells need them for support, when plasmolysis occurs, the cell becomes plamolysed and can no longer provide support.

3. Factors that affect the rate of movement of substances.

=These are all factors that can affect the rate of osmosis, active transport or diffusion of substances.


-Surface area to volume ratio = more surface area for certain volume for particles to move.
-Temperature = more energy provided for particles to move.
-Size of concentration gradient = larger concentration means more movement needed.

EXPERIMENTS = Remember the potato osmosis? :D Yes. The one where everyone was wondering what the cutting this was...and that it was a CORK BORER xD

RESPIRATION-
1. Understand that the process of respiration releases energy in living organisms.

We take in oxygen from the air,and glucose from our food in order to transform energy. By doing so we are respiring and producing water as well as carbon dioxide.

Animals and plants and other organisms do the same. They take in substances to release energy.

2. Describe the differences between aerobic and anaerobic respiration.

Anaerobic respiration takes place without oxygen and produces lactic acid as well as releasing energy, however we can not respire this way for long as a build- up concentration of lactic acid is not good for our body.
Aerobic respiration takes in oxygen and with glucose releases energy, we respire this way normally and it also produces small amounts water and carbon dioxide which we both breath out.

3. Write the word equation and balanced symbol equation for aerobic respiration in living organisms.
oxygen + glucose -> water + carbon dioxide (and energy)

6O₂ + C₆H₁₂O₆ -> H₂O + CO₂ (and energy)

REMEMBER -> You know the Mentalist? You know that epic Asian agent? His name is Agent Cho. So Glucose is CHO with the 6-12-6 ^^

4. Write the word equation for anaerobic respiration in plants and animals. 

glucose -> ethanol + carbon dioxide (and energy)

For us = glucose -> lactic acid (and energy)

Remember -> glucose and ethanol = drunk on sugar xD LOL. 

EXPERIMENTS:

-Living potato/onion slides.

-Non-living visking tubing...?

-Fermentation of yeast = alcohol :D :D :D 

-Potato osmosis

-Peas in a vacuum flask...

Heat denatures the enzymes disallowing it to function and it can no longer break down the substances. Heating would mean the conditions for doing so are no longer present.