Science

What is the atomic number?

The number of protons in an atom.

What is the mass number?

The total number of protons and neutrons.

In a neutral atom, how many electrons are there compared to protons?

The same number.

What does the group number tell you?

The number of valence (outer shell) electrons.

What does the period number tell you?

The number of electron shells.

What are the properties of metals?

Conduct electricity, malleable, ductile.

What are the properties of non-metals?

Poor conductors, brittle.

What are metalloids?

Elements with properties of both metals and non-metals.

What is an ionic bond?

A bond formed by the transfer of electrons.

Which elements usually form ionic bonds?

A metal and a non-metal.

What is a covalent bond?

A bond formed by sharing electrons.

Which elements usually form covalent bonds?

Two non-metals.

What is a metallic bond?

A sea of delocalised electrons shared between metal atoms.

Can non-metals form both ionic and covalent bonds?

yes

What is a synthesis reaction?

Two or more substances combine to form one product.

What is a decomposition reaction?

One compound breaks down into simpler substances.

What is a single displacement reaction?

One element replaces another in a compound.

What is a double displacement reaction?

Two compounds exchange ions

What is a neutralisation reaction?

Acid + Base → Salt + Water.

What is a precipitation reaction?

Two solutions react to form a solid precipitate.

What does it mean to balance an equation?

Have the same number of each type of atom on both sides.

Why must equations be balanced?

Because matter cannot be created or destroyed.

What pH range is acidic?

Less than 7.

What pH is neutral?

7

What pH range is basic/alkaline?

greater than 7

How does temperature affect reaction rate?

Higher temperature increases reaction rate.

Why does higher temperature increase reaction rate?

Particles have more kinetic energy and collide more often.

How does surface area affect reaction rate?

Larger surface area increases reaction rate.

How does concentration affect reaction rate?

Higher concentration increases reaction rate.

What is formed when a metal reacts with oxygen?

Metal oxide.

What are the products of hydrocarbon combustion?

Carbon dioxide and water.

What are the products of an acid and carbonate reaction?

Salt, water and carbon dioxide.

What does DNA stand for?

Deoxyribonucleic Acid.

What are the three parts of a nucleotide?

Phosphate, deoxyribose sugar, nitrogen base.

Which DNA bases pair together?

A-T and C-G.

Which RNA base replaces thymine?

Uracil (U).

What is replication?

Making an identical copy of DNA.

What is transcription?

DNA is copied into mRNA.

What is translation?

mRNA is used to make proteins.

What is the correct order of DNA processes?

Replication → Transcription → Translation.

What is genotype?

An organism's genetic makeup.

What is phenotype?

An organism's observable characteristics.

What does homozygous mean?

Having two identical alleles.

What is homozygous dominant? (T)

TT

What is homozygous recessive?

tt

What is heterozygous?

Tt

What is the genotype ratio for Tt × Tt?

1 TT : 2 Tt : 1 tt.

What is the phenotype ratio for Tt × Tt?

3 dominant : 1 recessive.

What is the ratio for a test cross?

1:1

Where are sex-linked traits located?

On the X chromosome.

Why are males more likely to show sex-linked traits?

They only have one X chromosome.

Which blood type is codominant?

AB

Which alleles produce blood type O?

ii

What is a mutation?

A change in the DNA sequence.

Can mutations be beneficial?

Yes

Can mutations be harmful?

Yes

What can embryonic stem cells become?

Any cell type in the body.

Why are embryonic stem cells controversial?

Ethical concerns about using embryos.

Who proposed natural selection?

Darwin and Wallace.

What did Lamarck incorrectly suggest?

Acquired traits can be inherited.

What is variation?

Differences between individuals in a population.

What is overproduction?

More offspring are produced than can survive.

Why does competition occur?

Limited resources

What happens to advantageous traits?

They are passed on to offspring.

What is natural selection?

The process where organisms with favourable traits survive and reproduce more successfully.

Name three types of evidence for evolution.

Fossils, structural similarities, genetic evidence.

What is speciation?

The formation of a new species.

What must happen for speciation to occur?

Populations become isolated and gene flow stops.

What is geographic isolation?

Physical barriers separate populations.

What is behavioural isolation?

Different behaviours prevent mating.

What is temporal isolation?

Populations breed at different times.

What is an adaptation?

A feature or behaviour that helps an organism survive and reproduce.

What is gene flow?

The movement of genes between populations through mating.

What is isolation?

When a population is split into separate groups that no longer mix.

What is divergence?

When species become more different over time due to different environments and selection pressures.

What are homologous structures?

Structures in different species that are similar because they share a common ancestor, but may have different functions.

What are analogous structures?

Structures with the same function but different structure, due to different evolutionary origins.

What is convergent evolution?

When unrelated species evolve similar traits because they live in similar environments.