Cells and movement across membranes

Question 1

What parts are in the animal cell?

Answer 1

Cytoplasm, nucleus, cell membrane, mitochondria

Question 2

What parts are in the plant cell?

Answer 2

Cytoplasm, nucleus, cell membrane, mitochondria, chloroplast, vacuole, cell wall

Question 3

What is the function of the cell membrane?

Answer 3

Controls the movement of substances into and out of the cell

Question 4

What is the function of the cytoplasm?

Answer 4

Jelly-like substance, where chemical reactions happen

Question 5

What is the function of the Nucleus?

Answer 5

Carries genetic information and controls what happens inside the cell

Question 6

What is the function of the Mitochondria?

Answer 6

Where aerobic respiration takes place and where ATP energy is produced

Question 7

What is the function of the vacuole?

Answer 7

Contains a liquid called cell sap which keeps the cell firm

Question 8

What is the function of the cell wall?

Answer 8

Made of cellulose which supports the cell and its shape and also prevents the cell from bursting when water is absorbed

Question 9

What is the function of the chloroplast?

Answer 9

Contains chlorophyll (green pigment) which absorbs light energy, photosynthesis occurs here

Question 10

What is the order of an experiment to show how to use a microscope using an onion?

Answer 10

1. Peel a thin layer of epidermis from the inside of a freshly cut onion
2. Lay the epidermis onto a glass slide
3. Add a drop of iodine solution to the onion epidermis on the glass slide
4. Gently lower a cover slip onto the glass slide
5. Use a light microscope to examine the slide, starting with the lowest power objective lens

Question 11

What is the equation for magnification?

Answer 11

Magnification = image size / actual size

Question 12

What does multicellular mean?

Answer 12

Made up of many cells, often specialised large organisms are multicellular

Question 13

Why are specialised cells more efficient?

Answer 13

Its adapted to its particular function, making it more efficient

Question 14

What are cells known as?

Answer 14

The basic units of life

Question 15

What is tissue?
What are some examples?

Answer 15

A group of similar cells carrying out a similar function. Examples would be muscle tissue, and nerve tissue

Question 16

What is an organ?
What are some examples?

Answer 16

An organ is made up of different tissues working together to carry out a function.
An example would be the heart, the leaf, and the brain

Question 17

What are organ systems?
What are some examples?

Answer 17

Organs are organised into organ systems. They often work together to produce organisms. Examples would be the digestive system and the respiratory system

Question 18

How are sperm cells, red blood cells, and nerve cells adapted to be more efficient?

Answer 18

Sperm cell - a tail to swim to the egg

Red blood cell - contain haemoglobin to carry oxygen around the body, has no nucleus and has a biconcave shape

Nerve cell - Long and insulated with a fatty layer to carry electrical impulses around the body

Question 19

What is diffusion?

Answer 19

The movement of molecules from an area of high concentration to an area of low concentration, moving down a concentration gradient. It does not require energy making it a passive process.

Question 20

How are oxygen and CO₂ linked to diffusion?

Answer 20

Oxygen moves into cells by diffusion and diffuses across the cell membrane.

Carbon dioxide moves out of cells by diffusion and diffuses across the cell membrane.

Question 21

What is a visking tubing model?

Answer 21

a non-living, artificial, selectively permeable membrane allowing small molecules to pass through pores whilst larger ones aren’t able to fit through.

Question 22

What are examples of large and small molecules in a visking tubing model?

Answer 22

Small molecules - iodine or water molecules

Large (solute) molecules - starch

Question 23

What is osmosis?

Answer 23

The movement of water molecules across a selectively permeable membrane from an area of high water concentration to an area of low water concentration, water molecules move down a concentration gradient. It does not require energy making it a passive process

Question 24

What is equilibrium?

Answer 24

a state of balance

Question 25

What is a independent variable?

Answer 25

The variable that you change or select

Question 26

What is a dependant variable?

Answer 26

The variable that you measure

Question 27

What is a control variable?

Answer 27

What is kept the same throughout the experiment

Question 28

What is the potato cylinder experiment?

Answer 28

Measuring changes in potato cylinder mass or length when submerged in a solution,it is often used to show water movement across a partially permeable membrane from a region of high water potential to low water potential.

Question 29

What is active transport?

Answer 29

a process where substances move from a low concentration to a high concentration, substances move against a concentration gradient.It requires energy in the form of ATP released from respiration

Question 30

What happens if respiration stops?

Answer 30

Active transport will stop as there is no energy available

Question 31

What happens during osmosis in a plant cell?

Answer 31

- (In dilute solution) The cytoplasm pushes against the cell wall and the cell becomes turgid (swollen with water) - (In concentrated solution) Water leaves the cell, causing the cytoplasm to shrink and pull away from the cell wall, causing plasmolysis, making the plant wilt.

Question 32

What happens during osmosis in an animal cell?

Answer 32

Animal cells do not have a cell wall. They change size and shape when put into solutions that are at a different concentration to the cell contents.

Question 33

What happens during osmosis in a red blood cell?

Answer 33

- Gain water, swell and burst in a dilute solution - Lose water and shrink in a concentrated solution (This does not happen inside the body due to kidneys ensuring the concentration of blood and cell contents are equal)

Question 34

What is the function of carrier proteins?

Answer 34

pick up specific molecules and take them through the cell membrane against the concentration gradient

Question 35

What are examples of active transport?

Answer 35

- Uptake of glucose by epithelial cells in the villi of the small intestine - Uptake ions from soil water by root hair cells in plants

Question 36

What are enzymes?

Answer 36

Proteins made by living cells

Question 37

What are enzymes known as?

Answer 37

Biological catalysts as they speed up the rate of chemical reactions within cells

Question 38

What are enzymes involved in?

Answer 38

metabolic reactions as they build up large molecules from small ones as well as breaking down large molecules into small ones

Question 39

What are enzymes shape?

Answer 39

folded into complex shapes that allow molecules to fit into them. The part of the enzyme where these molecules fit is called the active site

Question 40

What do the enzyme and the substrate form together to make?

Answer 40

The enzyme substrate complex

Question 41

What do the enzyme and substrate needs to do to complete an enzyme substrate complex?

Answer 41

Collide into eachother

Question 42

What is the optimum pH?

Answer 42

Where the enzyme is working at its fastest rate, the most successful collisions happen during the optimum. When the pH is too high the enzyme will denature.

Question 43

What are proteins made up of?

Answer 43

Long chains of amino acids, the order determines how the chain will fold to make the protein, giving them 3 dimensional shapes.

Question 44

What is differentiation?

Answer 44

Cells become specialised to perform different functions