Biology 3 and Physics

Question 1

How many strands is DNA made up of?

Answer 1

2

Question 2

What are the strands in DNA joined together by?

Answer 2

They are joined by 4 different chemicals.

A T C G

Question 3

What are the strands in DNA twisted to look like?

Answer 3

They are twisted together to form a double-helix shape.

Question 4

Why is understanding DNA important and useful?

Answer 4

Future study could lead to the prevention and cure of many diseases.

Question 5

What 2 scientist came up with the idea that DNA was twisted to form a double-helix?

Answer 5

James Watson and Francis Crick

Question 6

DNA: Which scientist carried out experiments using peas and what did they discover?

Answer 6

Gregor Mendel

He noticed that certain characteristics such as height and colour are passed from parents to their offspring.

Question 7

Genes: If your 2 genes are the same what is this called?

Answer 7

Homozygous

Question 8

Genes: If you have 2 genes which are different what is this called?

Answer 8

Heterozygous

Question 9

Different forms of the same genes are called …?

Answer 9

Alleles

Question 10

What are dominant alleles?

Answer 10

They are alleles which will always produce a characteristic in an organism. You only need one copy for the characteristic to appear in the organism.

Question 11

What are recessive alleles?

Answer 11

They are when you need both copies of the characteristic for it to appear.

Question 12

What is genetic modification?

Answer 12

It is when you alter an organisms characteristic to what you desire.

Question 13

Name 3 disadvantages to genetically modifying organisms.

Answer 13

1. people believe it is bad to interfere with organisms and using those techniques should be banned.
2. There may be unwanted risks.
3. genetically modified organisms bred with other species could result in new pathogens or superweeds being created.

Question 14

What can friction do?

Answer 14

• produce heat
• Wear things away
• slow things down
• make a noise

Question 15

What type of force is friction?

Answer 15

It’s the force that resists movement because of contact between surfaces.

Question 16

What is friction?

Answer 16

It’s the resistance to the rubbing motion.

Question 17

When particles get hot they….

Answer 17

create kinetic energy

Question 18

What does lubricating surfaces mean?

Answer 18

Making a surface smoother to reduce the amount of friction.

Question 19

What is drag force?

Answer 19

It’s the force acting on an object moving through air or water that causes it to slow down.

Question 20

How can you reduce drag?

Answer 20

By having a small cross-section, and being a streamlined shape.

Question 21

____ and ____ objects travel through the air more easily, whereas _____ and ____ objects travel through the air less easily.

Answer 21

Long
thin
short
wide

Question 22

Why does air resistance make you move slowly?

Answer 22

because it is creating friction between the air and you.

Question 23

What is hooks’ law?

Answer 23

If the extension doubles when you double the force then the object obeys hooks law. The graph of force against extension is a straight line.

Question 24

Turning forces: What are moments?

Answer 24

Moments are the turning effect about a pivot.

Question 25

Pressure in gases: Why does a balloon explode?

Answer 25

Because the air particles get compressed into the balloon and stretch the rubber. They collide with the balloon.

Question 26

Pressure in gases: What happens to a balloon when you put it in a freezer?

Answer 26

It shrivels up because the air particles create less pressure. The cold air particles move slower and slow down.

Question 27

When a balloon is heated it will _______.

Answer 27

explode

Question 28

There are ____ particles the _____ you go. ____ force is exerted on you. There is ____ pressure.

Answer 28

less
higher
less
less

Question 29

Pressure in gases: What is the calculation?

Answer 29

Pressure = Force
——–
Area

Question 30

The more water above you,….

Answer 30

the greater the downward force acts. The pressure will increase.

Question 31

What is up thrust?

Answer 31

it is an object that is partially, or completely, submerged experiences a greater pressure on its bottom surface than on its top surface.

Question 32

Pressure in liquids: Why are liquids impressible?

Answer 32

Because in a liquid the particles are touching and there is very little space between them.

Question 33

Why is the Earth like a magnet?

Answer 33

Because its core contains iron and nickel. It also has 2 poles, north and south.

Question 34

Magnets and magnetic fields: Why do the iron fillings become magnetised?

Answer 34

Because of the magnetic fields of the permanent magnet.

Question 35

What are permanent magnets?

Answer 35

they are always magnetic and attract magnetic materials.

Question 36

Which elements are magnetic?

Answer 36

iron, (steel), nickel and cobalt

Question 37

What are induced magnets?

Answer 37

they are materials which become magnetic when inside a magnetic field. They stop when they are removed from the field.

Question 38

What is an electromagnet?

Answer 38

It is when electricity is passed through the wire, it creates a magnetic field around it.

Question 39

What increases the strength of an electromagnet?

Answer 39

More coils, more current, a bigger iron core, more turns in the coil,

Question 40

How can we make a stronger magnetic effect?

Answer 40

If we make a coil of wire the combined effect of the magnetic field around each wire, results in a bar magnet being made.