Biology: Key Concepts, Hierarchy, and Genetic Processes

Biosphere

Is all life on earth and all places where life exist

Ecosystems

All living and non-living thing in a particular area and how they interact with each other

Community

All populations of organisms occupying a particular area

Population

All members of a specific species that occupy the same area

Organisms

individual living things

Organs

Groups of tissues that work together to perform a specific function or related functions

Tissues

Groups of specialised cells with a common function.

Cell

Lifes fundamental unit of structure and function (smallest unit of life)

Organelles

Specialised intracellular structures that carry out a specific function

Molecules

Groups of two or more atoms held together by chemical bonds

What are the 5 unifying themes

organization, information, energy and matter, interactions, evolution

Explain Organisation

The hierarchy of life is arranged in such a way that structure are related at each step in the hierarchy. Each new step is more complex, thus leading to the formation of emergent properties and the ability to carry out functions of life.

Explain Information

Lifes processes and functions involve the expressing of genetic material. Genetic information is stored in specific sequences of DNA molecules and is inheritable from parents to offspring.

Explain Energy and Matter

Energy is cycled through an ecosystem. This energy is used by organisms to do work and is eventually lost to the environment in the form of heat.

Explain Interactions

Organisms continuously interact with physical factors (both biotic and abiotic). Interactions amongst different organisms affect an ecosystem in many ways

Differentiate DNA, gene, chromosome, and genome.

DNA is a nucleic acid that stores genetic information

A gene is a specific sequence of nucleotides that codes for a polypeptide

A chromosome is a singular, condensed DNA molecule

A genome is the summation of all the genes in an organism

Describe transcription

Copying the gene in DNA into a complementary mRNA sequence

Describe translation

Process where the information carried by mRNA is used to produce proteins at the ribosome with the assistance of tRNA.

What are emergent properties?

New properties that arise with each step upward in the hierarchy of life, owing to the arrangement and interactions of parts as complexity increases.

What is the systems approach to biology?

It is the study of a biological system through the observation of the interactions of its various parts

What is gene expression?

the process of converting information from gene to cellular product

What are the pyrimidines?

cytosine, thymine, uracil

What are the purines?

Adenine and Guanine

What is a genome?

The entire set of genetic material in an organism (genetic library)

What is genomics?

the study of whole sets of genes in different organisms

What is proteomics?

the study of the full protein set encoded by a genome

What is a proteome?

The full range of proteins expressed by the genome

What is bioinformatics?

the application of computational methods to the storage and analysis of biological data

What are plants (in terms of energy)?

Producers (autotrophs)

Organisms that ingest plants and other organisms for energy are called?

Consumers (heterotrophs)

What does energy enter and leave the ecosystem as?

Enters as light, exits as heat

What happens to chemical elements/nutrients in an ecosystem?

They are recycled

How are certain biological processes regulated?

Through feedback mechanisms

Outline negative feedback with an example

Negative feedback is when a biological product downregulates its own production in order to maintain homeostasis - regulation of body temperature, regulation of blood glucose, regulation of blood pressure

Outline positive feedback with an example

Positive feedback is when a product upregulates its own production in order to maintain homeostasis - blood clotting, lactation, childbirth

What is climate change?

Directional change in global climate which lasts 3 decades or more

What is evolution?

Evolution is the concept that organisms are modified descendants of common ancestors

State the prokaryotic domains

Archaea and Bacteria

Outline the 4 classifications of the eukaryotic domain

Animal, Protist, Fungi, Plant

What were Darwins main 2 points?

- Species show evidence of descent with modification from common ancestors

- Natural selection causes descent with modification

Outline natural selection

Natural selection is the process by which organisms that are better adapted to the selective pressures of a given environment are more likely to survive and reproduce

Summarise the steps in the scientific method

- Observation

- Hypothesis

- Experimentation

- Results

- Conclusion

State the 3 subatomic particles, their charge, and where they are found

Proton - positively charged (nucleus)

Neutron - uncharged (nucleus)

Electron - negatively charged (arranged in orbitals)

Differentiate between atomic number and mass number

Atomic number is the number of protons in an atoms nucleus whereas mass number is the number of protons + neutrons in an atoms nucleus

What is meant by atomic mass?

The summation of the weight of all of the subatomic particles found in an atom

What is an isotope?

An isotope is a form of an element that differs in the number of neutrons it has (+ a neutron)

What are radioisotopes?

A radioisotope is a form of an element with an unstable nucleus (- a neutron usually through radioactive decay)

What is an electron orbital?

a restrictive three-dimensional space around the nucleus of an atom where an electron will be found

What is the formula for determining how many electrons will be found in an electron shell?

2n^2

What is the valence shell?

The outermost shell of an electron

How do you determine if an atom is stable?

If it has a full valence shell

How are atomic bonds formed?

When 2 atoms have incomplete valence shells they transfer or share electrons to achieve stability

How is an ionic bond formed?

Through the electrostatic attraction between two oppositely charged ions. When a cation (metal) transfers an electron to an anion to achieve stability

How is a covalent bond formed?

When two atoms share pairs of valence electrons

Differentiate between a non polar covalent bond and a polar covalent bond

In a non-polar covalent bond, atoms share electrons equally amongst each other. In a polar covalent bond atoms are shared unequally amongst each other due to a significant difference in electronegativity.

Which are stronger in aqueous environments covalent bonds or ionic bonds?

Covalent bonds

Define electronegativity

Electronegativity refers to an atoms ability to attract and hold electrons in a covalent bond

What are the Pauling electronegativity values?

- > 1.7 - ionic

- < 0.4 - non-polar covalent

- 0.4 - 1.7 - polar covalent

What is the most electronegative element?

Fluorine

What characteristic of carbon allows it to be the backbone of all organic molecules?

It has 4 valence electrons, which allows it to form 4 stable covalent bonds

What is a hydrocarbon? Give examples

A hydrocarbon is a molecule composed entirely of hydrogen and carbon atoms. An example would be methane

What is a structural isomer?

Structural isomers are two or more compounds that have the same chemical formula but differ in their structural formula

What is a cis trans isomer?

Cis trans isomers are compounds that have the same covalent bonds but differ in their spatial arrangement. These structures are usually diastereomers arranged around a carbon-to-carbon double bond.

What is an enantiomer?

A pair of molecules that are non-superimposable mirror images of each other. These structures have a chiral carbon and can rotate polarised light (optically active). Usually, only one form of the enantiomer is biologically active

What is a functional group?

They are chemical groups that affect molecular function by being directly involved in chemical reactions

Name the 7 functional groups most important to life

- Hydroxyl

- Carboxyl

- Carbonyl

- Sulfhydryl

- Methyl

- Phosphate

- Amine(o)

How is ATP used for energy?

ATP stores potential to react with water. When it reacts, the energy released can be used by the cell to perform work

What are macromolecules?

Macromolecules are large organic molecules usually built from repeated smaller organic subunits

What is a polymer?

A large molecule composed of repeating subunits called monomers

What are monomers?

Smaller units which can be linked together to form larger molecules

What is the link between two monomers called?

Glycosidic linkage

Which macromolecule is not a polymer?

Lipids

What are the 4 classes of macromolecules?

- Carbohydrates

- Proteins

- Lipids

- Nucleic acid

What are monosaccharides?

Simple sugars that can be linked together to form larger carbohydrates. Examples include glucose, fructose, and galactose

What are disaccharides?

2 monosaccharides joined together through a glycosidic linkage. Examples include sucrose, maltose, lactose

Draw the linear version of glucose

Draw the ring version of glucose

Differentiate between alpha and beta d-glucose

In alpha glucose, both the OH groups point downwards, whereas in beta glucose, one of them points upwards

What are the 4 structures of protein?

primary - specific sequence of amino acids

secondary - the type of folding a polypeptide chain undergoes

tertiary - the 3d structure of a protein

quaternary - the interactions between two or more polypeptide chains

What are some of the bonds that form the tertiary structure of a protein?

Disulphide bridge, ionic bond, hydrogen bond, and van der Waals forces

What is denaturation?

When a protein loses its native form and becomes biologically inactive due to a high temperatures or substantial fluctuation in pH

What are nucleic acids composed of?

A monomer called a nucleotide

What are the 3 components of a nucleotide?

Pentose sugar (Ribose or Deoxyribose), Phosphate group, and nitrogenous base

What are the differences between DNA and RNA

DNA: Double-stranded, Thymine, deoxyribose, and stores genetic information

RNA: Single-stranded, Uracil, Ribose, and copies genetic information