science sec 1

Question 1

what is the definition of science?

Answer 1

science is the study of the natural and physical world

Question 2

what are the scientific method ?

Answer 2

1. ask questions
2. propose a hypothesis
3. make observations
4. collect evidence

Question 3

definition of dependent variable ?

Answer 3

variable that is measured in the experiment

Question 4

definition of independent variable ?

Answer 4

variable that is changed to test the effects on the dependent variable

Question 5

definition of controlled variable ?

Answer 5

variable that is kept the same

Question 6

difference between luminous and non luminous flame

Answer 6

difference | luminous | non luminous

1. air hole | closed | open
2. flame | unsteady | steady
3. temperature | hot | very hot
4. colour | orange and light blue | light blue and dark blue

Question 7

advantages of medicine

Answer 7

can cure diseases

Question 8

disadvantages of medicine

Answer 8

may increase the risk of antibodies-resistant ‘superbugs’

Question 9

advantages of technology

Answer 9

improve our lives

Question 10

disadvantages of technology

Answer 10

it can be abused and can cause harm to society and the environment

Question 11

what are cells ?

Answer 11

living organisms that are made up of small buildings units of life known as cells

Question 12

what are the two types of organisms

Answer 12

1. UNIcellular - single cell organism (amoeba)

2. MULTIcellular - multiple cell organism

Question 13

function of nucleus

Answer 13

1. usually largest in the structure
2. spherical shape
3. responsible for cell division
4. controls cell activities (eg. repair worn-out parts)
5. keeps the cells alive
6. contains chromosome

Question 14

function of chromosome

Answer 14

1. long thread-like structure found in nucleus
2. contains genes that carry genetics materials that determine heredity
3. passed down from parents to off springs

Question 15

function of vacuole (animal cell)

Answer 15

1. fluid-filled space

2. contains water and other nutrients needed for living organism to live small and numerous

Question 16

function of cytoplasm

Answer 16

1. jelly like substance
2. contains chemical and organelles that carry out special functions
3. serves as a site where chemical reactions take place

Question 17

function of cell membrane

Answer 17

1. thin membrane surrounding the cell
2. partially permeable structure that only allows certain structures to pass through
3. serves as a boundary between the cell and the external environment control substances entering or leaving the cell