Topic A: Basics: Cells and classification

Question 1

The Cell concept?

Answer 1

All living organisms are made from cells. A simply organism may have different types of specialized cells which all do different jobs. Different types of organisms contain different cells.

Question 2

What are Plants?

Answer 2

• Multicellular organisms
• Their cells contain chloroplasts- able to carry out photosynthesis
• Their cells have cellulose cell walls
• They store carbohydrates as starch or sucrose.

Question 3

What are Animals?

Answer 3

• These are multicellular organisms
• They have no cell walls
• They usually have nervous coordination and are able to move from one place to another
• They often store carbohydrate as glycogen.

Question 4

What are Fungi?

Answer 4

-Usually organised into a mycelium made from thread-like structures called hyphae, which contain many nuclei
-Some examples are single-celled
-Their cells have walls made of chitin
-They feed by extracellular secretion of digestive enzymes onto food material and absorption of the organic products (saprotrophic nutrition)
-They may store carbohydrate as glycogen.
DON’T CONTAIN CHLORPLASTS

Question 5

What are Protoctists?

Answer 5

These are microscopic single-celled organisms
Some, like Amoeba, that live in pond water, have features like an animal cell
Some like Chlorella, have chloroplasts and are more like plants
A pathogenic example is Plasmodium, responsible for causing malaria.
ALL HAVE NUCLEUS
SOME HAVE CELL WALL

Question 6

What are viruses?

Answer 6

• These are small particles, smaller than bacteria
• They are parasitic and can reproduce only inside living cells
• They infect every type of living organism
• They have a wide variety of shapes and sizes
• They have no cellular structure but have a protein coat and contain one type of nucleic acid, either DNA or RNA
• Examples include the tobacco mosaic virus, the influenza virus (causes ‘flu’) and the HIV virus (causes AIDS)

Question 7

What is a pathogen?

Answer 7

-A pathogen is anything that causes a disease. Pathogens include:

• Bacterium (example: bacterial meningitis or strep throat)
• Virus (example: hepatitis A, hepatitis B, and hepatitis C)
• Fungus (example: athlete’s foot)

Question 8

What are the main characteristics that all living organism share?

Answer 8

Movement 
Respiration
Sensitivity 
Growth
Reproduction
Excretion 
Nutrition

Question 9

Function of the nucleus?

Answer 9

Controls what the cell does. It contains instructions to make new cells.

Question 10

Function of Cytoplasm?

Answer 10

Chemical reactions take place inside the cytoplasm, to keep the cell alive.

Question 11

Function of the Cell membrane?

Answer 11

This is a thin layer of skin around the cell membrane, it gives the cell its shape and controls what comes in and out of the cell.

Question 12

Function of Mitochondrion?

Answer 12

The cell’s power station. they convert energy into forms that are useful for the cell.

Question 13

Function of the cell wall?

Answer 13

Covers the thin cell membrane. it is made of tough cellulose that strengthens the wall.

Question 14

Function of chloroplasts?

Answer 14

These are found in cells that carry out photosynthesis. they contain chlorophyll to trap light energy.

Question 15

Function of Large permanent vacuole?

Answer 15

a plant cell has a large permanent vacuole filled with a liquid called cell sap.

Question 16

Level of organisation?

Answer 16

Atom, smallest unit that a chemical element is made of.
Molecule: 2 or more atoms (same different) chemically combined.
Organelle, structures in the cell that perform a particular job.
Cell, Unit of all living organism.
Tissue: Many cells of the same kind with a particular function.
Organ, Several tissues combined to perform a particular task.
Organ system: several organs which act together to perform a general function
Organism: An independent organism.

Question 17

Kingdoms are subdivided into Phyla……..

Answer 17

Phylum - classes 
class - orders 
order - families 
family - genera 
genus - species

Question 18

Examples of Plants?

Answer 18

-Examples include flowering plants, such as a cereal (for -example maize), and a herbaceous legume (for example peas or beans).

Question 19

Examples of Animals?

Answer 19

-Examples include mammals (for example humans) and insects (for example mosquito).

Question 20

Examples of Fungi?

Answer 20

-Examples include Mucor (hyphal example) and yeast (single cell example).

Question 21

Define Diffusion?

Answer 21

The movement of particles form an area of high concentration to an area of low concentration, down a concentration gradient until equilibrium is reached. Substance that the cells need are diffused through the membrane.

Question 22

Define Osmosis?

Answer 22

Movement of water from an area of high water potential to a low water potential down a water potential gradient through a semi-permeable membrane, this requires no energy. Used root hair cells to absorb water.

Question 23

Define Active Transport?

Answer 23

The movement of particles against the concentrating gradient (low-high) THIS REQUIRES ENERGY. Used to transport proteins into and out of the cell.

Question 24

Structure of Fungi?

Answer 24

• Usually organised into a mycelium made from thread-like structures called hyphae, which contain many nuclei.
• Some are single celled.

Question 25

What are Fungi cell walls made of?

Answer 25

Chitin.

Question 26

Experiment to investigate Diffusion?

Answer 26

Using Agar jelly with phenolphthalein and dilute sodium hydroxide. Fill a beaker with dilute hydrochloric acid. To investigate the rate, these cubes can be cut into different sizes. You can then record the rate at which the cubes turn colourless as the acid diffuses into the agar jelly and neutralizes the sodium hydroxide.

Question 27

Experiment to investigate Osmosis - potato cylinders?

Answer 27

Cut potato into cylinders, and put them into beakers with different sugar solutions (one should be pure and another saturated) Then some in between. You can measure the length of the cylinders then leave them and then after an hour take measurements again . if the cylinders have drawn water in by osmosis we know that the water concentration of water in the potato is less than the water concentration in the beaker and visa versa.

Question 28

Experiment to investigate Osmosis - Visking Tubing?

Answer 28

(Explain setup) Pour some suger solution down the glass tube into the visking tubeing. Put the visking tubing in a beaker and measure where the sugar solution comes up to on the glass tube. Leave this overnight, then measure where the liquid is in the glass tube. Water should be drawn into the visking tubing by osmosis and this will force the liquid up the glass tube. Inside the visking tubing the water concentration is low, outside it is high.

Question 29

The Main factors effecting the movement of substances?

Answer 29

Surface are to volume ratio.
Temperature.
Concentration gradient.

Question 30

Example of a Protoctists?

Answer 30

Amoeba

Question 31

Example of Bacteria?

Answer 31

Salmonella

Question 32

What is a Bacteria?

Answer 32

Bacteria are living cells and, in favourable conditions, can multiply rapidly. Once inside the body, they release poisons or toxins that make us feel ill.
NO NUCLEUS

Question 33

Ways structure of virus differs from bacteria?

Answer 33

no cell wall
no cell membrane
smaller

Question 34

Example of a Virus?

Answer 34

HIV virus

Question 35

Example of a disease caused by a virus?

Answer 35

AIDS

Question 36

Which organisms have a protein coat?

Answer 36

Virus

Question 37

Are all pathogens?

Answer 37

Virus

Question 38

Contain DNA in nucleus?

Answer 38

Fungus

Question 39

Respire?

Answer 39

Bacteria and Fungus

Question 40

What is Saprotrophic nutrition

Answer 40

Normally used by Fungi, they feed by extracellular secretion of digestive enzymes onto food material and absorption of the organic products (saprotrophic nutrition)