Module 2 - Organisation of living things

Question 1

How are cells arranged in a multicellular organism?

Answer 1

Multicellular organisms have interdependant cells that in most organisms have become highly specialised. These sepcialised cells give rise to different tissue types and the formation of different organs.

Question 2

Define
1. organelle
2. cell
3. tissue
4. organ
5. system
6. organism

Answer 2

1. A membrane-bound compartment within eukaryotic cells. Each of these performs a specific role to aid cellular activity.
2. The basic building block of living things
3. Groups of similar specialised cells working together
4. Groups of tissues working together to perform a function for an organism, e.g heart kidney, skin, leaf
5. Groups of organs working together to perform a function for an organism, such circulation, digestion or immunity.
6. An individual animal, plant, or single-celled life form.

Question 3

What is an autotroph? and a heterotroph?

Answer 3

Autotrophs are producers who prepare their own food. Heterotrophs are consumers who depend on other sources for their food. Classified into. These can be classified as photoautotrophs and chemoautotrophs.

Question 4

compare nutrient and gas requirements between autotrophs and heterotrophs?

Answer 4

Autotrophs and heterotrophs both require inorganic and organic substances - autotrophs require CO2. - Autotrophs obtain glucose (or their food) through self-manufacture while heterotrophs must obtain organic nutrients by consuming autotrophs or other heterotrophs.

Question 5

what are varying respiratory systems in plants and animals?

Answer 5

Lungs, gills, skin in frogs, leaves in plants.

Question 6

How can organisms expel waste?

Answer 6

Through digestive system, or cell membrane in cells.

Question 6

What is the transpiration-cohesion-tension theory? (movement in xylem of plants)

Answer 6

The transpiration cohesion-tension mechanism describes the transport of water in trees. When water evaporates from leaves (transpiration), tension (suction) is created, drawing more water up the lead. Because water molecules are cohesive when one is pulled up, the others will follow.

Question 7

What is the difference between physical and chemical digestion?

Answer 7

Physical digestion involves breaking down food into smaller peices without making chemical changes, like chewing and grinding of stomach muscles. Chemical involves use of chemicals in breakdown of food, like digestive enzymes such as amalayse in saliva and pepsin in stomach.

Question 8

What is poo (faeces) made out of?

Answer 8

Live and dead bacteria, dead cells like red blood cells (that is why it is brown), solids, mostly water and indigestible fibres.

Question 9

what are the components of blood?

Answer 9

plasma, red blood cells, white blood cells, and platelets.

Question 10

what internal gas exchange?

Answer 10

Internal respiration occurs in the metabolizing tissues, where oxygen diffuses out of the blood and carbon dioxide diffuses out of the cells.

Question 11

what is external gas exchange?

Answer 11

External respiration occurs in the lungs where oxygen diffuses into the blood and carbon dioxide diffuses into the alveolar air.

Question 12

how is gas exchanged in plant leaves?

Answer 12

When a plant is carrying out photosynthesis carbon dioxide needs to move from the air into the leaf. It does this by diffusing through small pores called stomata. At the same time oxygen moves out of the leaf through the stomata.

Question 13

what is the xylem?

Answer 13

the vascular tissue in plants which conducts water and dissolved nutrients upwards from the root and also helps to form the woody element in the stem.

Question 14

what is the phloem?

Answer 14

the vascular tissue in plants which conducts sugars and other metabolic products downwards from the leaves.

Question 15

what is closed and open circulatory system?

Answer 15

Blood can flow through vessels inside the body, such as arteries and veins. This type of circulation is called closed circulation (mammals). Open circulation happens when there are no vessels to contain the blood, and it flows freely through the cavities of the body. This type of circulatory system is found in arthropods (like insects). They have a tube like heart with a number of chambers, which pumps a fluid called haemolymph directly into the tissues, where it moves around the body cavity freely.

Question 16

How does the diaphragm’s movement control inhalation and exhalation?

Answer 16

As the diaphragm goes down, chest cavity expands, bringing air into the lungs. When it is pushed up, chest cavity contracts and air is exhaled.