topic 1 - key concepts in biology

Question 1

What are eukaryotic cells

Answer 1

Animal and plant cells

Question 2

What do animal cells contain and their functions

Answer 2

Nucleus - holds genetic information
Cell membrane - holds the cell together and what goes in and out
Mitochondria - powerhouse of the cell
Ribosomes - protein synthesis
Cytoplasm - gel l8e substance where chemical reactions happen

Question 3

What do plant cells contain and their functions

Answer 3

Nucleus – hold genetic material
Cell membrane – holds cell together and control what goes in and out
Mitochondria – powerhouse of the cell
Vacuole – contain cell sap, maintains the internal pressure to support cell
Ribosomes – side of protein synthesis
Cell wall – made of cellulose, supports the cell and strengthens it
Chloroplast – photosynthesis occurs, contains a green substance called chlorophyll

Question 4

What do bacteria cells contain and their functions

Answer 4

Chromosomal DNA – controls the cells activities and replication, it flows free in the cytoplasm
Ribosomes
Cell membrane
Plasmid DNA – small loops of extra DNA that aren’t part of the chromosome
Flagella – a long hair like structure that rotates to make the bacteria move

Question 5

What are the two specialised cells?

Answer 5

Sperm and egg ciliated epithelial cells

Question 6

How are sperm cells adapted to the function

Answer 6

Acrosome – stores enzymes needed to digest its way through the membrane of the egg cell
Haploid nucleus
Mitochondria – provide energy needed to swim
Tail – it can swim to the egg

Question 7

How are egg cells adapted to function?

Answer 7

Nutrients in the cytoplasm for feeding embryo
Haploid nucleus
Changes of structure to stop more sperm getting in after fertilisation

Question 8

How are ciliated epithelial cells adapted to their function?

Answer 8

Have Celia on the top of the surface cell to move substances along the surface of the tissue

Question 9

Changes in microscopes

Answer 9

Like microscopes were invented in the 1590s they work by passing light through the specimen. They let us see things like nuclear and chloroplast and we can also use them to study living cells.

Electron microscopes were invented in 1930s they use electrons rather than light. Electron microscopes have a higher magnification and resolution than light microscopes, so they let us see much smaller things in more detail like the internal structure of mitochondria and chloroplasts.

Question 10

What is order of units

Answer 10

Milli
Micro
Nano
Pico

Question 11

Core practical microscopy

Answer 11

Use a thin slice of your specimen
Take a clean slide and use a puppet to put one drop of water in the middle of it – this will secure the specimen in place. The new tweezers to place your specimen on the side.
at a drop stain if your specimen is completely transparent or colours
Place a cover slip at one end of the specimen holding it at our angle with a mounted needle and carefully lower it onto the slide. Press it down gently so that no air bubbles are trapped under it. Then click the slide onto the stage.
Select the lowest powered object
Use the course adjustment knob to move the stage up so that the IPS, move to stage downwards until the specimen is nearly in focus
Then adjust the focus with the final adjustment knob until you get a clear image

Question 12

What is the equation for total magnification?

Answer 12

Eye piece lens magnification X objective lens magnification

Question 13

Wha5 is the equation for magnification

Answer 13

Image size divided by real size

Question 14

How do enzymes work?

Answer 14

Every enzyme has a active site – the part where it joins onto its substrate catalyse the
Enzymes usually only work with one substrate. They are to have a high specific for the sub
This is because, for the enzyme to work, the substrate has to fit into the active site. If the substrate shape doesn’t match the active side shape, then the reaction will be catalysed.

Question 15

How can enzymes be denatured?

Answer 15

If an enzyme reaches its optimum pH, temperature then it can start to denature this changes the active site and won’t be able to fit into the substrate anymore and it will not catalyse the reaction

Question 16

How does substrate concentration affect enzyme activity?

Answer 16

Substrate concentration also affects the rate of reaction – the higher substrate concentration, the faster the reaction. This is because it’s more likely that the enzyme will meet up and react with a substance molecule.

Question 17

Investigating pH on enzymes - core practical

Answer 17

put a drop of iodine solution into every well of a spotting tile
Play some Bunsen burner on a heat proof mat and a tripod and goes over the Bunsen burner. Put a beaker of water on top of the tripod and heat the water until it is 35°C. Try to keep the temperature of the water constant throughout the experiment .
use a syringe to add 3 cm³ of Amla solution and 1 cm³ of a buffer solution with a pH of 5 to a boiling tube. Using test powders, put the boiling tube into the beaker of water and wait for five minutes.
next use a different syringe to add 3 cm³ of a start solution to the boiling tube.
immediately makes the contents of the boiling tube and start a stop clock.
when are you doing? Solution? Remains brownie orange, starch is no longer present.
repeat the whole experiment with both of the solutions at different PH values to see how pH affect a time taken for the start should be broken down

Question 18

What is the calculation for rate?

Answer 18

1000 divided by time

Question 19

What does the enzyme carbohydrate breakdown?

Answer 19

Convert carbohydrates into simple sugars

Question 20

What does proteins convert?

Answer 20

Proteins convert proteins into amino acids

Question 21

What does lipases convert?

Answer 21

Lipids into glycerol and fatty acid

Question 22

What is diffusion and how does it transport substances?

Answer 22

Diffusion is the net movement of particles from the area of high concentration to an area of lower concentration
Only very small molecules can diffuse through cell membranes

Question 23

What is osmosis and how does it transport substances?

Answer 23

I suppose that movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration
Things like water can pass through
He tries to even up the concentration either side of the membrane

Question 24

What is active transport and how to transport substances?

Answer 24

Active transport is the movement of particles across a membrane against the concentration gradient
it requires energy

Question 25

Core practical potatoes

Answer 25

Prepares solutions of different concentrations raging from pure water to a very concentrated solution
Use a cork or a cup potato into the same size pieces
Divide the centres into groups of three useless balance to measure the mass of each group
Place one group in each
Leave the cylinders in the solution for at least 40 minutes
Remove the suns impact dry gently with a paper towel. This removes access water from the surface of the cinders, so you get a more accurate measurement of the final masses.
Wait each group again and
The only thing that you should change in this experiment is a solution concentration

Question 26

How to calculate percentage change in mass of the potatoes

Answer 26

Final minus initial mass divided by initial mass times 100