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What cell type has a nucleus?

Eukaryotic cells

What cell type has a permanent vacuole?

Plant cells only

What cell type has plasmids?

Prokaryotic cells

What is structure A in plant cell diagram?

Vacuole

What is structure B in plant cell diagram?

Chloroplast

What is structure C in plant cell diagram?

Cell wall

How do you adjust microscope to see Slide A more clearly?

Use coarse focus knob, then fine focus knob

How do you adjust microscope to see Slide B more clearly?

Move Slide B under objective lens / change to higher power lens

Magnification formula + calculate for 112mm image, 280µm actual

Mag = Image ÷ Actual. 112 ÷ 0.28 = 400x

Which letter on diagram is the stomach?

C

What enzyme type is made in the stomach?

Protease

What pH is the stomach?

Acidic

Why is the stomach acidic?

Produces hydrochloric acid/HCl

Which organ produces bile?

Liver

How does bile help digestion?

Increases surface area of fats

What reagent tests for protein?

Biuret reagent

What reagent tests for starch?

Iodine solution

What reagent tests for sugar?

Benedict's solution

Safety precaution for Benedict's test?

Wear goggles / use water bath not flame

Which tests were positive in the results?

Benedict's and iodine tests only

Why aren’t starch molecules absorbed?

Too large / must be broken into glucose

What pathogen causes gonorrhoea?

Bacterium

What pathogen causes measles?

Virus

2 ways body stops pathogens entering?

1. Skin barrier 2. Mucus + cilia trap/move them

How does immune system defend the body?

Phagocytes engulf pathogens. Lymphocytes make antibodies/antitoxins. Memory cells give faster response next time.

Why can’t antibiotics treat HIV?

Antibiotics kill bacteria, HIV is a virus

2 ways to prevent HIV spread?

1. Use condoms 2. Don’t share needles

Why do people with AIDS die from other infections?

HIV damages the immune system

Why are some alpha particles deflected in scattering experiment?

They are positively charged

Why are most alpha particles not deflected?

Atom is mainly empty space

What did alpha scattering show about mass?

Mass is concentrated at centre of atom

What are Group 7 elements called?

Halogens

Which element is most reactive with gold?

Fluorine

Word equation for gold + chlorine?

gold + chlorine → gold chloride

Mass of Cl that reacts with 3.94g Au if product = 6.07g?

6.07 - 3.94 = 2.13g

Calculate Mr of AuCl3. Ar Au=197, Cl=35.5

197 + 3(35.5) = 303.5

Definition of relative formula mass Mr?

Sum of relative atomic masses of all atoms in formula

Group of periodic table for lithium + sodium?

Group 1

Name of positively charged nuclear particle?

Protons

Name of neutral nuclear particle?

Neutrons

Mass number of lithium atom shown?

7

How does Na atom become Na+ ion?

Loses

(a) Draw one line from each cell structure [3 marks, box-ticker]

Nucleus → Eukaryotic cells

Permanent vacuole → Plant cells only

Plasmid → Prokaryotic cells

(b) What are names of structures A, B and C? [3 marks, box-ticker]

A → Vacuole

B → Chloroplast

C → Cell wall

(c) Describe how student should adjust microscope to see cells on Slide A more clearly [2 marks, explanation]

Use coarse focus knob to bring cells into focus, then fine focus knob to sharpen the image.

(d) Describe how student should adjust microscope to see cells on Slide B more clearly [1 mark, box-ticker]

Move Slide B under the objective lens / change to higher power objective lens

(e) Calculate magnification of drawing [3 marks, explanation]

Magnification = Image size ÷ Actual size. Image = 112 mm, Actual = 280 µm = 0.28 mm. Magnification = 112 ÷ 0.28 = 400x

(a) Which organ is the stomach? [1 mark, box-ticker]

C ✓

(b) What type of enzyme is produced in stomach? [1 mark, box-ticker]

Protease ✓

(c) Which term describes pH in stomach? [1 mark, box-ticker]

Acidic ✓

Reason why stomach is this pH [1 mark, box-ticker]

Stomach produces hydrochloric acid / HCl

(d) Which organ produces bile? [1 mark, box-ticker]

Liver ✓

How does bile help in digestion? [1 mark, box-ticker]

It increases the surface area of fats ✓

(f) Draw one line from each food molecule to reagent [3 marks, box-ticker]

Protein → Biuret reagent

Starch → Iodine solution

Sugar → Benedict's solution

(g) Give one safety precaution using Benedict's solution [1 mark, box-ticker]

Wear safety goggles / use water bath not direct flame

(h) Which tests show positive results? [1 mark, box-ticker]

Benedict's and iodine tests only ✓

(i) Starch molecules not absorbed - give one reason [1 mark, box-ticker]

Starch molecules are too large to be absorbed

(a) Draw one line from each disease to pathogen [2 marks, box-ticker]

Gonorrhoea → Bacterium

Measles → Virus

(b) Give two ways body prevents pathogens entering [2 marks, box-ticker]

1. Skin acts as a physical barrier
2. Mucus + cilia trap and move pathogens out

(c) Describe how immune system defends body [8 marks, explanation]

Phagocytes engulf and digest pathogens by phagocytosis. Lymphocytes produce antibodies that bind to specific pathogens to destroy them, or produce antitoxins to neutralise toxins. Memory cells are made so the immune response is faster if the same pathogen enters again.

(d) Give one reason antibiotics cannot be used to treat HIV [1 mark, box-ticker]

Antibiotics only kill bacteria, HIV is a virus

(e) Give two ways to prevent spread of HIV [2 marks, box-ticker]

1. Use condoms
2. Do not share needles/syringes

(f) Why do people with AIDS die from different infection? [1 mark, box-ticker]

HIV damages the immune system ✓

(a) Some alpha particles are deflected because… [1 mark, box-ticker]

positively charged

(b) Why are most alpha particles not deflected? [1 mark, box-ticker]

The atom is mainly empty space ✓

(c) What was one conclusion from alpha scattering experiment? [1 mark, box-ticker]

The mass is concentrated at the centre of the atom ✓

(d) What are Group 7 elements known as? [1 mark, box-ticker]

Halogens ✓

(e) Which element will be most reactive with gold? [1 mark, box-ticker]

Fluorine ✓

(f) The word equation for the reaction is: [1 mark, box-ticker]

gold + chlorine → gold chloride

(g) Calculate mass of chlorine that reacts with 3.94 g of gold [2 marks, explanation]

Mass = 6.07 - 3.94 = 2.13 g

(g) Calculate relative formula mass of gold chloride AuCl3 [2 marks, explanation]

Mr = 197 + 3(35.5) = 197 + 106.5 = 303.5

(g) Relative formula mass (Mr) = _ [2 marks, explanation]

Sum of relative atomic masses of all atoms in the formula

(a) In which group of periodic table are lithium and sodium? [1 mark, box-ticker]

Group 1 ✓

(b)(i) Some particles in nucleus have positive charge - name? [1 mark, box-ticker]

Protons ✓

(b)(ii) Some particles in nucleus have no charge - name? [1 mark, box-ticker]

Neutrons ✓

(b)(iii) The mass number of this atom of lithium is: [1 mark, box-ticker]

7 ✓

(c)(i) A sodium atom changes into a sodium ion by: [1 mark, box-ticker]

losing an electron ✓

(c)(ii) A sodium ion has: [1 mark, box-ticker]

a positive charge ✓

(c)(iii) The ions in sodium chloride are held together by: [1 mark, box-ticker]

electrostatic forces ✓

(a)(i) Which substance is a gas? [1 mark, box-ticker]

C ✓

(a)(ii) Which substance is a liquid? [1 mark, box-ticker]

B ✓

(a)(iii) Which substance is an element? [1 mark, box-ticker]

C ✓

(a)(iv) Which substance is made of ions? [1 mark, box-ticker]

D ✓

(d) Sodium chloride is ionic - tick 2 properties [2 marks, box-ticker]

High melting points ✓
Strong bonds ✓

(e)(i) Calculate relative formula mass of NaCl [2 marks, explanation]

Mr = 23 + 35.5 = 58.5

(e)(ii) The relative formula mass of a substance in grams is one: [1 mark, box-ticker]

mole ✓

(f) What are nanoparticles? [1 mark, box-ticker]

Particles with at least one dimension between 1-100 nm

(d) Gamma radiation consists of: [1 mark, box-ticker]

Wave of energy ✓

(e) Explain differences between properties of alpha, beta, gamma [6 marks, explanation]

Charge: Alpha +2, Beta -1, Gamma 0
Ionisation: Alpha strongest, then beta, gamma weakest
Penetration: Alpha stopped by paper, beta by aluminium, gamma needs lead/concrete
Distance in air: Alpha few cm, beta ∼1 m, gamma several metres

(a) Draw a line of best fit on Figure 2 [1 mark, practical]

Straight line through middle of points, through origin

(b) What conclusion can be made from Figure 2? [1 mark, explanation]

Proportional relationship between energy transferred and temperature change

(c) Explain why student's calculated value of specific heat capacity was higher than expected [2 marks, explanation]

Heat lost to surroundings as block not insulated. Smaller ΔT recorded → higher c value since c = E / mΔT.