Life Sciences
Life science skills
Scientific Method
1. The question
What is happening? How is it happening? When is it occurring?
2. Introduction
Background research will ensure that you are not investigating something that has already been
investigated
3. Identify Variables
The dependent variable: thing you want to measure (mass of tomatoes)
The independent variable: factor that changes which will influence dependent variable (how
much light is exposed to tomatoes)
Fixed variable: are all kept the same in all trials under the investigation (fertilizer, species of
tomato...)
4. Hypothesis
Write down a statement or prediction as to what you think the outcome of your investigation
will be. Be specific, be testable, prediction not question.
5. Aim
State what you are going to be investigating, to determine…; To show that…
6. Apparatus
Size of beakers, test tubes, specialized equipment, all chemicals and quantities
7. Method
An experiment is a tool that you design to find out if your ideas about your question are right or
wrong. The experiment is the most important part of the scientific method. The method should
be written out so that a stranger would know exactly what to do and how to do it.
8. Results
Present your results in a table or graph, all results need to be recorded
9. Analysis of results or discussion
Discuss if there is any relationship between your independent variable and dependent variable
10. Evaluation of results
Validity: Was it fair? Reliability: If repeated, will results be similar?
Discuss any experimental errors that may have occurred
11. Conclusion
The conclusion needs to link the results of the aim and hypothesis in a short paragraph
, Chemistry of life
Atom- The smallest of matter (living/non-living) that can take part in a chemical reaction
Molecule- Two or more atoms that combine with one another chemically
Element- A pure substance that is not made up of other simpler substances
Compound- A pure substance that is made up of simpler substances (elements), two or more elements that
are chemically combined
Cell- Organelles that form a living unit that can perform all functions of life, smallest unit of life
Tissue- Group of similarly differentiated cells perform a common function
Organs- Tissues with different functions work together to perform a common function
Organ system- Organs join in a system with a common function/s
Organism- Consists of several organ systems that work together to maintain homeostasis
Cohesion- The force that holds molecules for a single material together
Adhesion- The attractive force between 2 different substances that are in contact with each other
Characteristics explained
7 basic characteristics of life
• Organisms can grow and develop from their original size and
shape • Nutrition
• Organisms regulate their own metabolic processes. • Response to stimuli
Chemical reactions and energy transfer processes are known • Growth
as the metabolism of the cell and metabolic reactions take • Reproduction
place to maintain homeostasis • Respiration
• Organisms react to stimuli by color changes, changes in light • Excretion
intensity, temperature, pressure, and water potential • Movement
• Organisms reproduce as they all develop from already
existing organisms
Organic Compounds MRS GREN
Chemical compounds that contain the element Carbon (C) and are M- Move
produced by living organisms such as Carbon (C), Hydrogen (H), R- Respire
S- Stimuli
Oxygen (O) and some may contain Nitrogen (N), Phosphorus (P) and
Sulphur (S)
G- Growth
R- Reproduce
E- Excrete
N- Nutrition
Inorganic Compounds Water (H20)
Chemical compounds that do not contain the Water is the most important inorganic compound for living
element Carbon (C) and are not produced by organisms
living organisms It works as a solvent, Mineral salts dissolve in water
All chemical reactions of living organisms occur in water
The exceptions of this are Carbon dioxide It is a reagent during hydrolysis; water breaks down polymers
(CO2), Carbon monoxide (CO) and down into monomers
Carbonates (-CO3) It transports nutrients, metabolic waste, gases, and mineral
salts
Hydrophilic -water soluble and react with water Lubricant for chewing and swallowing
Hydrophobic- do not dissolve in water Regulates body temperature and gives shape and rigidity
, Mineral salts
Mineral Salts are inorganic substances that are needed and absorbed by living organisms
Mineral salts can be divided into 2 groups
Macroelements- mineral salts needed in large quantities
Microelements- mineral salts needed in small quantities
MACROELEMENTS
Element Function Deficiency
Builds strong bones and
teeth Humans: rickets
Necessary for blood (children), osteomalacia
Calcium (Ca) coagulation and osteoporosis
Plays a role in
permeability of cell Plants: weak root
membranes growth
Plays a role in muscle
contractions
Builds strong bones and
teeth, Component of Humans: Seldom occurs
Phosphorus (P) ATP
Component of nucleic Plants: Stunted plant
acids growth
Part of Phospholipids
Important for
maintaining water
balance in the body Humans: Muscle cramps
Sodium (Na) Facilitates the
functioning of nerves Plants: Unknown
and muscle contraction
Controls rhythm of heart
Important for
maintaining water
balance Humans: seldom occurs
Potassium (K) Facilitates functioning
of muscles and nerves Plants: Yellow and
Helps regulate heart brown leaf margins
rhythm
Necessary to activate
plants enzymes
MICROELEMENTS
, Element Function Deficiency
Helps to form
hemoglobin that Humans: Anemia
Iron (Fe) transports O2 in the
blood Plants: Chlorosis
Helps to form (yellowing of leaves)
chlorophyll
Iodine (I) Component of the
hormone thyroxine Humans: goitre
which is secreted by the (swelling of the neck)
thyroid gland
Fertilizers and eutrophication REMEMBER
In over-utilized soils the soil becomes depleted of Phosphates (PO4) and Nitrates (NO3)
mineral salts. Fertilizers are continuously worked into are also minerals, but they are
The soil to counteract this mineral deficiency compounds not elements
Fertilizers mostly contain Nitrogen, Potassium and
phosphate Phosphate ions- Main source of
phosphorus in plants
A lot of these minerals from the fertilizers are
leached washed away and lands in rivers and dams. Nitrate ions- Main source of Nitrogen
The phosphate causes a drastic increase in algae and that is needed for protein synthesis and
blocks the many water plants which results in the it for part of DNA and RNA and is also
death of many waters plants needed for synthesis of chlorophyll
The dead organic material must be decomposed, and
it requires oxygen meaning it will deplete the oxygen Synthesis- to make
supply in the water
This phenomenon is known as eutrophication
Life science skills
Scientific Method
1. The question
What is happening? How is it happening? When is it occurring?
2. Introduction
Background research will ensure that you are not investigating something that has already been
investigated
3. Identify Variables
The dependent variable: thing you want to measure (mass of tomatoes)
The independent variable: factor that changes which will influence dependent variable (how
much light is exposed to tomatoes)
Fixed variable: are all kept the same in all trials under the investigation (fertilizer, species of
tomato...)
4. Hypothesis
Write down a statement or prediction as to what you think the outcome of your investigation
will be. Be specific, be testable, prediction not question.
5. Aim
State what you are going to be investigating, to determine…; To show that…
6. Apparatus
Size of beakers, test tubes, specialized equipment, all chemicals and quantities
7. Method
An experiment is a tool that you design to find out if your ideas about your question are right or
wrong. The experiment is the most important part of the scientific method. The method should
be written out so that a stranger would know exactly what to do and how to do it.
8. Results
Present your results in a table or graph, all results need to be recorded
9. Analysis of results or discussion
Discuss if there is any relationship between your independent variable and dependent variable
10. Evaluation of results
Validity: Was it fair? Reliability: If repeated, will results be similar?
Discuss any experimental errors that may have occurred
11. Conclusion
The conclusion needs to link the results of the aim and hypothesis in a short paragraph
, Chemistry of life
Atom- The smallest of matter (living/non-living) that can take part in a chemical reaction
Molecule- Two or more atoms that combine with one another chemically
Element- A pure substance that is not made up of other simpler substances
Compound- A pure substance that is made up of simpler substances (elements), two or more elements that
are chemically combined
Cell- Organelles that form a living unit that can perform all functions of life, smallest unit of life
Tissue- Group of similarly differentiated cells perform a common function
Organs- Tissues with different functions work together to perform a common function
Organ system- Organs join in a system with a common function/s
Organism- Consists of several organ systems that work together to maintain homeostasis
Cohesion- The force that holds molecules for a single material together
Adhesion- The attractive force between 2 different substances that are in contact with each other
Characteristics explained
7 basic characteristics of life
• Organisms can grow and develop from their original size and
shape • Nutrition
• Organisms regulate their own metabolic processes. • Response to stimuli
Chemical reactions and energy transfer processes are known • Growth
as the metabolism of the cell and metabolic reactions take • Reproduction
place to maintain homeostasis • Respiration
• Organisms react to stimuli by color changes, changes in light • Excretion
intensity, temperature, pressure, and water potential • Movement
• Organisms reproduce as they all develop from already
existing organisms
Organic Compounds MRS GREN
Chemical compounds that contain the element Carbon (C) and are M- Move
produced by living organisms such as Carbon (C), Hydrogen (H), R- Respire
S- Stimuli
Oxygen (O) and some may contain Nitrogen (N), Phosphorus (P) and
Sulphur (S)
G- Growth
R- Reproduce
E- Excrete
N- Nutrition
Inorganic Compounds Water (H20)
Chemical compounds that do not contain the Water is the most important inorganic compound for living
element Carbon (C) and are not produced by organisms
living organisms It works as a solvent, Mineral salts dissolve in water
All chemical reactions of living organisms occur in water
The exceptions of this are Carbon dioxide It is a reagent during hydrolysis; water breaks down polymers
(CO2), Carbon monoxide (CO) and down into monomers
Carbonates (-CO3) It transports nutrients, metabolic waste, gases, and mineral
salts
Hydrophilic -water soluble and react with water Lubricant for chewing and swallowing
Hydrophobic- do not dissolve in water Regulates body temperature and gives shape and rigidity
, Mineral salts
Mineral Salts are inorganic substances that are needed and absorbed by living organisms
Mineral salts can be divided into 2 groups
Macroelements- mineral salts needed in large quantities
Microelements- mineral salts needed in small quantities
MACROELEMENTS
Element Function Deficiency
Builds strong bones and
teeth Humans: rickets
Necessary for blood (children), osteomalacia
Calcium (Ca) coagulation and osteoporosis
Plays a role in
permeability of cell Plants: weak root
membranes growth
Plays a role in muscle
contractions
Builds strong bones and
teeth, Component of Humans: Seldom occurs
Phosphorus (P) ATP
Component of nucleic Plants: Stunted plant
acids growth
Part of Phospholipids
Important for
maintaining water
balance in the body Humans: Muscle cramps
Sodium (Na) Facilitates the
functioning of nerves Plants: Unknown
and muscle contraction
Controls rhythm of heart
Important for
maintaining water
balance Humans: seldom occurs
Potassium (K) Facilitates functioning
of muscles and nerves Plants: Yellow and
Helps regulate heart brown leaf margins
rhythm
Necessary to activate
plants enzymes
MICROELEMENTS
, Element Function Deficiency
Helps to form
hemoglobin that Humans: Anemia
Iron (Fe) transports O2 in the
blood Plants: Chlorosis
Helps to form (yellowing of leaves)
chlorophyll
Iodine (I) Component of the
hormone thyroxine Humans: goitre
which is secreted by the (swelling of the neck)
thyroid gland
Fertilizers and eutrophication REMEMBER
In over-utilized soils the soil becomes depleted of Phosphates (PO4) and Nitrates (NO3)
mineral salts. Fertilizers are continuously worked into are also minerals, but they are
The soil to counteract this mineral deficiency compounds not elements
Fertilizers mostly contain Nitrogen, Potassium and
phosphate Phosphate ions- Main source of
phosphorus in plants
A lot of these minerals from the fertilizers are
leached washed away and lands in rivers and dams. Nitrate ions- Main source of Nitrogen
The phosphate causes a drastic increase in algae and that is needed for protein synthesis and
blocks the many water plants which results in the it for part of DNA and RNA and is also
death of many waters plants needed for synthesis of chlorophyll
The dead organic material must be decomposed, and
it requires oxygen meaning it will deplete the oxygen Synthesis- to make
supply in the water
This phenomenon is known as eutrophication
