0610 biology (all)

@Chapter@04 Biological Molecules

1. List the chemical element of the following substance:
Carbohydrate. [1]

CHO

Fat. [1]

CHO + others
store energy

Protein. [1]

CHON + others

p.s. N comes from Nitrate ions

2. State the smallest subunits of the following molecules: Starch. [1]

Glucose
Simple sugar
Monosaccharide

State the smallest subunit of fat. [1]

Glycerol + fatty acid

State the smallest subunit of protein. [1]

Amino acid

State the smallest subunit of glycogen. [1]

Glucose
Simple sugar
Monosaccharide

State the smallest subunit of cellulose. [1]

Glucose
Simple sugar
Monosaccharide

State the smallest subunit of DNA. [1]

nucleotides/bases

3. How to identify starch? [3]

Add 2 ml of food sample and 2 ml of iodine solution into a test tube,
if the colour changes from *brown to dark blue*,
it means the presence of starch in food sample

4. How to identify glucose/reducing sugar in sweat potato? [5]

Benedict's test
1. *grind* the sweat potato to get juice,
2. add *2 ml* of sweet potato juice into a test tube,
3. add *2ml* of *Benedict's solution* into the same test tube,
4. use *test tube holder* to put the test tube into a *water bath*,
5. *Heat* the water bath,
6. wait for *5 minutes*,
7. if the colour changes *from blue to brick red*,
it means the presence of reducing sugar;
8. during the practical, wear *protective goggles*,

5. How to identify protein in milk? [3]

Biuret test
(if the sample is insoluble, grind the sample to make juice or dissolve it)
Add *2ml* Biuret reagent into a test tube( CuSO4+ NaOH),
Add *2ml* milk into the same test tube,
If the colour changes from blue to purple, it means the presence of protein.

6. How to identify fat in peanut? [3]

Crush peanuts into smaller pieces ,
Use 10 ml ethanol to dissolve fat from peanut,
Add 2ml of fat-ethanol solution into a test tube,
Add 2ml of water into the same test tube,
Gently shake the test-tube,
If the colour of the solution changes from colourless to milky white, it means the presence of fat

p.s. emulsification

7. How to identify vitamin C in apples? [3]

1. Crush apples to make juice,
2. Add 2 ml apple juice into a test tube,
3. Add 2ml *DCPIP* into the same test tube,
4. if the colour changes *from blue to colourless*
it means the presence of VC.

(other methods: Starch + iodine as indicator,
VC reacts with iodine, so the indicator
changes from dark blue to colourless)

8. Explain that different sequences of amino acids give different shapes to protein molecules. [3]

1. 3D shape of protein is determined by
bonds, e.g. peptide bonds, hydrogen bonds,
ionic bonds
2. Change in sequences of amino acids will
change the peptide bonds, hydrogen bonds and ionic bonds between the amino acid subunits

p.s.
1. Sequence of amino acids forms primary structure of protein.
2. Hydrogen bonds between N and H of different amino acid subunit forms the secondary structure.
3. Bonds between R-groups of amino acids form the tertiary structures.
4. Difference in sequences of amino acid subunits change the 3D shape of protein ,

These change the primary, secondary and tertiary structure of protein.

9. Explain why enzyme is specific to catalyse one reaction?
(Explain why antibody is specific to one type of antigen?) [3]

1. Active site of enzyme has specific shape,
2. which is *complementary* to the shape of substrate;
3. Substrate perfectly fits into active site to form *enzyme-substrate-complex*;
4. which lowers the *activation energy* and allows faster reaction rate;
5. When reaction occurs, products are formed,
products have different shapes, so they leave the active site;
6. Enzyme does not change, and can be re-used;

10. Write down 6 functions of water? [6]

As universal solvent;
As transporting agent;
As cooling agent;
As supporting agent;
As a reactant;
To maintain the stable environment temperature

11. Describe the structures of a DNA molecule. [3]

1. Contains two strands, which form double helix;
2. Each contains nucleotides,
3. The phosphate and sugar of nucleotides form the backbones of the chain;
4. Bases of nucleotides on each chain join together by hydrogen bonds;
5. A joins with T, C joins with G

Edited by Leo Wang

王昱超编辑

protein

chemical element: CHO N,

chemical equation: C(a)H(b)O(c)N(d),

subunit: amino acids

function: 1. tissue repair , 2.growth

DNA

Chemical element: CHO N P

subunit: bases / nucleotides
(ATCG)

function : contain genes which codes for information to make protein.

structure of DNA :

1. Contains two strands, which form double helix;
2. Each contains nucleotides/bases,
(3. The phosphate and sugar of nucleotides form the backbones of the chain;)
4. Bases (of nucleotides) on each chain join together by hydrogen bonds;
5. A joins with T, C joins with G

@Chapter@05 Enzyme

Define enzyme. [2]

A protein functions as a biological catalyst, which can speed up reactions without changing itself, lowering the activation energy of reactions.

Define Catalyst. [2]

A chemical substance which speeds up reactions without being changed by the reactions, lowering the activation energy.

2. Explain why enzymes are important for organism? [2]

1. Speed up all the metabolic reactions
2. Without enzymes, reactions are too slow
or cannot happen or need very high temperature
3. e.g. no respiration

3. What are the 6 properties of enzymes? [6]

1. a protein
2. a catalyst
3. works best at optimum temperatures
4. denatures at higher temperatures
5. works best at optimum pH
6. specific to a reaction

4. Explain how enzyme can catalyze one reaction?
Explain lock and key hypothesis. [5]

1. Active site has specific shapes
2. the shape of active site is complementary to a specific substrate
3. substrate-enzyme-complex is formed
4. which lowers the activation energy, reaction rate is increased
5. products have different shapes, products leave the active site
6. enzyme/active site can be reused

5. Describe and explain how temperature affects enzyme activities. [5]

Description:
1. trends: increase, peak, decrease
2. use of data and unit
3. compare
Explain:
1. rate increases: higher kinetic energy,
substrates and enzyme move faster,
more successful collision occurs
more enzyme-substrate-complex is formed
2. rate decreases, active site of enzyme
is damage/denatured,
which cannot bind with substrate

6. Describe how to set up a practical to observe how ph affects enzyme activities.
I) What is the DV? [1]

DV is dependent variable, the variable we observe
Enzyme activity

What is the IV? [1]

IV is independent variable, the variable we put into the observation.
pH value

What is the CV? [1]

CV is Controlled variables, other variables which might change enzyme activities and must be kept constant,
to make sure that iv is the only variable that changes,
and is the only variable which is responsible to the changes of DV.

Factors of enzyme activities.

pH
temperature
time duration
substrate concentration
enzyme concentration

ii) Use H2O2 ---> H2O + O2 as an example, describe the process of observing how temperature affects enzyme activities. [5]

1. IV: set up at least 5 IVs, one near optimum temperature , (e.g. 5 water bath 15, 25, 35, 45, 55 degree C)
2. DV: describe how to observe DV (e.g. bubbles per minute)
3,4: Describe how to control CVs (e.g. use pH buffer/control of pH value, the same amount/ concentration of enzyme and substrate, the same apparatus, same time duration)
5. Reliability: repeat 3 times
6. Safety: wear goggles

7. Explain why pH can affect enzyme activities. [2]

1. pH value affects the bonds within the protein molecules,
2. pH values can change the structures of active sites,
so substrates cannot perfectly fit into the active site to form *enzyme-substrate-complex*

Applications of enzymes. [?]

Biological washing powder/ baby food/extract juice/making lactose free milk:
1. Enzymes to break down large insoluble molecules into small soluble molecules

Lipase breaks down lipid into glycerol and fatty acids;

Proteases break down protein into amino acids

Carbohydrase breaks down carbohydrate into glucose

Pectinase breaks pectin into glucose in making juice

Lactase breaks down lactose into galactose and glucose

Explain the use of Fermenter. [?]

Used to cultivate microbes,
microbes release enzymes out of cells into the environment,
Supply oxygen for respiration of microbes in fermenter,

Control pH (pH probe, adding NH3 or acid) and temperature (temperature probe, water jacket)

Supply soluble food source, e.g. sucrose, NH3, amino acid

Edited by Leo Wang

王昱超编辑

@chapter@01 Classification

1.1 MRS.Gren

1. What are the seven features of life? [1]

Mrs. Gren

2. Define the following term
Define: Movement. [2]

The ability to change place or position.

Define: Reproduction. [2]

The ability to produce fertile offspring.

Define: Sensitivity. [2]

1. The ability to detect stimuli;
2. The ability to respond to stimuli

Define: Growth. [2]

1. An increase in dry mass;
2. By increasing cell numbers or cell sizes
or both;

Define: Respiration. [2]

1. The series of chemical reactions
2. Within living cells,
3. which releases energy from food molecules, e.g. glucose, amino acids

Define: Excretion. [2]

1. Removal from cell of
2. waste products of metabolism
3. toxic materials
4. excess substances out of requirement

Define: Nutrition. [2]

1. Taking in of nutrients
2. which can supply enough energy and raw materials for metabolism

Define: Development. [2]

1. the increase in complexity
2. cells become (more) specialised
3. to have different functions and form different tissues and organs
(Stem cells)

1.2 Concept and use of a classification system

1. Choose the following word : morphology , anatomy , external feature,
evolutionary relationship, more , less,
i) scientists normal classify organisms according to their a) ___________,
through the study of b) _____________ and c)_________________, the purpose of classification is
to discover d) ________________________ between species.
Because close relatives share e) _______
similar features , both genetically and physically. [5]

a) external feature
b) morphology
c) anatomy
d) evolutionary relationship
e) more

ii) Explain why DNA sequences can provide more accurate means of classification. [2]

1. DNA is stable/lower mutation rate
2. Relative species share some unique DNA
3. External features may not be obvious/may be damaged.

2. i) What is the definition of species? [1]

1. A group of organisms of a population
2. which is able to reproduce and produce fertile offspring.

ii) Explain why different species cannot have fertile offspring? [2]

1. Different species have different genes
2. They have different numbers of chromosomes.
3. Sperms and eggs of different species are not able to fertilise

3. i) What is the binomial system to name an organism? [1]

The name of Genus and the name of species.

ii) Bila cella, Bila bila, Tolia cella, Cogo tita
Which one or ones are closely related to Bila kalialo,
explain your reason. [2]

Bila cella and Bila bila,
because they belong to the same genus, Bila.

1.3 Features of organisms

1. Bacteria
i) Draw and label a bacterium cell. [5]

O-clear outline, no gap, same thickness line
S-big enough, around 60% of spaces provided
D-detail, draw what you see
L-label at 3 structures you are 100% for sure

ii) What are the plant features of bacteria? [1]

have cell wall

iii) What are the animal features of bacteria? [2]

no large central vacuole
no chloroplast
store food as glycogen

iv) List 2 structures which can be found in bacteria only. [1]

plasmid
nucleoid
flagella (flagellum)
pilli

v) Explain why bacteria are suitable in gene technology? [3]

1. fast growth
2. asexual reproduction, offspring are able to produce the same products
3. lack of ethical concerns over the manipulation and growth of bacteria
4. genetic codes are shared with all other organisms
5. presence of plasmid

2. Virus
i) Draw and label a virus. [5]

O
S
L

ii) Is a virus a cell ( ) [1]
List 3 functions of a living cell [3]

Virus is not a cell.
3 functions are any 3 out of Mrs.Gren

iii) Explain why antibiotics can not be used to treat virus-infecting disease? [2]

1. Antibiotics affect the formation of bacterial cell wall
2. Virus does not have cell wall,

3. Fungi
i) Draw and label a mushroom [5]

OSDL
show, sporangium, feeding hyphae

ii) What are the functions of feeding hyphae? [2]

1. release enzymes out of cell on to dead matter
2. e.g. *proteases*, which break down protein into amino acid.
*Lipase*, breaks down fat to fatty acids + glycerol.
*Carbohydrase*, breaks down carbohydrates into glucose
3. Larger insoluble to small soluble molecules
4. Allows the absorption of small soluble substances through diffusion and active transport across the cell membrane.

iii) Do fungi release enzymes in the digestive area of their body to digest food inside their body? [1]

Yes,
p.s. Bacteria and fungi carries out internal digestion

iv) How can fungi carry out asexual reproduction? [2]

through mitosis
to produce spores
when sporangium matures, it bursts to release spores
spores are able to develop into new fungi

v) How can fungi spread to new colonies? [2]

1. spores are light
2. when sporangium matures, it bursts to release spores into the air.
3. wind brings spores to new colonies
4. spores can develop into new fungi

vi) What are the plant features of fungi cell? [1]

1. cell wall (made of chitin)

vii) What are the animal features of fungi? [2]

1. no large central vacuole
2. store food as glycogen
3. do not have chloroplasts

p.s. cell wall of fungi contains chitin

4. Protoctists
IF the organisms can not be classified into bacteria or fungi or plant, or animal, then they are placed into protoctists.
i) List 2 features of protoctists. [2]

1. unicellular
2. have nucleus

5. Plant
i) Draw and label a plant cell. [5]

O—1
S—1
D—1
L— 2

ii) List 3 differences between dicot and monocot. [3]

1. leaves: dicot has broad leaves, while monocot has narrow leaves
2. vein: dicot has branching network veins, while monocot has parallel veins
3. seed: dicot has 2 cotyledons, monocot has only 1 cotyledon
4. number of petals: dicot has 4s or 5s, monocot has 3s

iii) List 3 features of fern. [3]

1. reproduce through spores (no flowers, no seeds)
2. have vascular bundles (xylem + phloem)
3. have leaves, stems and roots

6. Animals
i) Vertebrate
(a) List 5 classes in phylum vertebrate. [3]

fish
amphibians
reptiles
birds
mammals

(b) List at least 1 unique features of each class

Fish. [1]

1. skin covered with slimy scales
2. use fins for swiming
3. use gills for breathing

Amphibian. [1]

1. skin is moist, smooth and scaleless

Reptile. [1]

skin is covered with dry scale

Birds. [1]

1. skin is covered by feather
2. have wings
3. have beak

Mammal. [1]

1. has hair/fur
2. external ears
3. 4 types of teeth
4 . mammary gland
5. others, have sweat glands, 4-chambered heart, diaphragm

ii) Arthropods
(a) List 3 common features of all arthropods [1]

1. jointed legs
2. segmented body
3. exoskeleton

(b) list 4 classes in arthropods. [2]

insects,
arachnids,
crustaceans
myriapods

(c) list at least one special feature of each class mentioned in ii) (b)
Insects. [1]

1. 3 pairs of jointed legs
2. body has 3 parts: head, thorax, abdomen
3. antennae
4. may have wings
5. compound eyes

Arachnid. [1]

1. 4 pairs of legs
2. body has 2 parts: cephalothorax + abdomen

Crustacean. [1]

1. 5-20 pairs of legs
2. body has 2 parts: cephalothorax + abdomen
3. has antennae
4. compound eyes

Myriapod. [1]

1. >20 pairs of legs
2. >20 body segments
3. has antennae

1.4 Dichotomous keys

Enjoy your Revision Journey!

Good luck for IGCSE Biology Exam (0610)

Edited by Leo Wang

王昱超编辑

@Chapter@ 02 Cell

1. Draw and label an animal cell. [4]

o s d l--cell membrane, cytoplasm, nucleus

2. Draw and label a plant cell. [5]

o
s
d
l-cell wall, cell membrane, chloroplast, cytoplasm

3. Cell structure and function
State the functions of the following structures.
i) Cell membrane. [2]

1. Separate cell content from the environment
2. Control materials in and out of cells

ii) Cytoplasm. [1]

1. Site of metabolic reactions
2. support the shape of the cell

iii) Nucleus. [2]

1. Contains genes/chromosomes, which code for proteins
2. Control normal activities of cells

iv) Mitochondria. [1]

1. Site of respiration
2. Release energy

v) Rough Endoplasmic Reticulum. [1]

Involved in protein synthesis;
ribosome attaches on Rough Endoplasmic reticulum.

vi) Ribosome. [1]

1. Involved in protein synthesis
2. Ribosome attaches on mRNA
ribosome moves about mRNA，
ribosome reads the codes of mRNA,
3. Ribosome attaches tRNA, which carries amino acids to ribosome,
then amino acids are joined together to form a protein according to the code of mRNA

vii) Cell wall. [2]

1. Protects and supports cells
2. Prevents the cell from bursting by absorbing too much water

viii) Chloroplast. [2]

1. Site of photosynthesis
2. To produce glucose from carbon dioxide and water

iv) Vacuole. [1]

May store water/pigment/waste product