Y9 Cells And Enzymes Flashcards
What are cells?
Cells are the building blocks of life.
What can cells form?
They join together to form a tissue, more of this form an organ, and more of these form an organ system.
What different types of cells are there?
Cells can be eukaryotic or prokaryotic.
What are Eukaryotic cells?
Eukaryotic cells are more complex and include all animal and plant cell parts.
What are prokaryotic cells?
Prokaryotic cells are simpler like the bacteria. They don’t have all the plant and animal cell parts.
Name 3 specialised cells of animals.
Sperm, egg, red blood cell, silica cells and white blood cells.
Describe a plant cell.
Plant cells usually have a regular shape, and made up of different parts. Some of the parts are in a animal cell as well as in a plant cell, for instance: Cell membrane, cytoplasm and nucleus (also mitochondria), however some parts are found in only plant cells: Chloroplast, vacuole and cell wall.
What is the Cytoplasm?
Jelly-like substance, where chemical reactions happen.
What are specialised cells?
Specialised cells are cells that have a structure which makes them adapted to what they are meant to do.
How is the sperm cell adapted to its job?
These sperm cells are specialised because of the long tale at the back of their body and their sharp noses.
How is the egg cell adapted to its job?
The functions are to carry the DNA of the female and to help the developing embryo in the early stages.
How are ciliated epithelial cells adapted to their job?
They have mucus attached to them to catch dust and bacteria.
What do microscopes do?
Microscopes make things seem bigger so you can see lots of details like individual cells.
What are microscopes used to do?
Microscopes are used to study cells.
How do microscopes work?
They normally use lenses. Lenses and bent bits of glass. In microscopes, they are convex. This means they are fat in the middle.
How do you identify different microscopes?
You can measure microscopes with their magnification (how much bigger they make things) and their resolution (how well they can distinguish between two points).
Also, you can get light microscopes and electron microscopes.
Describe light microscopes.
Light microscopes are the most common microscopes and also the cheapest. They work by shining light through the sample and putting the light through some lenses so it all seems bigger. They were invented in the 1590s and can magnify things by about 1000x. This means they can see things like chloroplasts and nuclei.
Describe electron microscopes.
Invented in the 1930s electron microscopes use electrons instead of light. This allows for a much higher magnification and resolution.
They are used to see much smaller things such as the internal structure of mitochondria and chloroplasts. However electron microscopes only show black and white colour.
Describe standard form.
Microscopes can see very small things so using standard form is important for reading numbers quickly. Big numbers with lots of zeros can be simplified. For example, 0.0078 could be written as 7.8x10(to the -3). This makes reading long numbers easier and quicker. All you need to do is move the decimal point left or right and times by 10 to the power of how many places you moved it.
What are enzymes?
They are catalysts created by living things.
They are biological catalysts.
They only speed up the useful chemical reactions in our body.
The unuseful chemical reactions will not be triggered by enzymes.
What do enzymes do?
Enzymes are meant to speed up reactions so they can be done faster.
Enzymes keep us alive as without them we would not be able to complete reactions in our body fast enough so I we would die.
They reduce the need for high temperatures in reactions.
What can effect enzymes?
Temperature - rate of enzyme-catalysed reaction: hotter = faster.
Too hot and enzyme will be denatured.
pH - can interfere with bonds and denature the enzyme.
What are enzymes benefits?
Digestive enzymes can be used to break/digest difficult products -Gluten -Casein -Lactose To get more nutrients
How can you detect starch?
The enzyme amylase catalyses the breakdown of starch to maltose. It’s easy to detect starch using iodinesolution, if starch is present. The iodine solution will change from browny-orange to blue-black.
Describe Benedict’s Reagent.
Benedict’s Reagent Test is used to test for (simple) carbohydrates. The Benedict’s test identifies (reducing) sugars , which have free ketone or aldehyde functional groups. Benedict’s solution can be used to test for the presence of glucose in urine.
What does the emulsion test test for?
This test tests for lipids in any sample.
It works as the lipids don’t dissolve into the other liquid and are left as droplets.
What does the biuret test test for?
This test determines whether or not there is protein in the substance.
How can you calculate the calories in food?
When testing for energy in food the food burns which heats the water, as the temperature increases the thermometer records the temperature from there you can calculate how many calories are in the food.
What does the food industry use a calorimeter for?
The calorimeter is used in the food industry as you can use it to measure the amount of calories per grams. This is important for people in the food industry as it is a product requirement to show how many calories are in a product.
What is diffusion?
The movement of air and liquid particles.
Air with high density moves to an area of air with low density.
What is osmosis?
Osmosis is when water molecules move across a partially permeable membrane from a region of higher water concentration to an area of lower water concentration.
A partially permeable membrane is a membrane with very small holes in it.
What is active transport?
Active transport is when ions move across a cell membrane into a region of higher concentration.
This is good because it allows nutrients to be taken into the blood even though it is the wrong way. Active transport is the opposite of diffusion.
Active transport requires energy to happen whereas diffusion doesn’t require any energy. This makes it passive.
List the three variables in the osmosis practical.
The independent variable is the concentration of sucrose solution.
The dependant variable is the mass change.
The controlled variable is the temperature and the volume change.
List the equipment used in the osmosis practical.
Borer various amount of sucrose tap water Scalpel Paper towels Scales Ruler Timer Potato Tile Measuring Cylinder
How do we investigate osmosis?
Putting potato chips into different concentrations of sucrose solution to show the effect of what different water concentrations have on them.
What is the method we use to investigate osmosis?
- Prepare sucrose solution of different concentrations from pure water to a concentrated sucrose solution.
- Use a cork to cut the potato into the same size pieces.
- Divide the potato cylinders in the solution for about 40 mins. They must get the same amount of time.
- Place one group in each solution.
- Remove the cylinders and pat them with a towel. This will remove water from the surface of the cylinders.
- Weigh each group again and record your results.
