Year 10 Biology

Define distance.

Distance is the total length of the path traveled by an object, regardless of direction. It is a scalar quantity measured in meters (m).

Define displacement.

Displacement is the straight-line distance in a specific direction from an object's starting point to its ending point. It is a vector quantity measured in meters (m).

What is speed?

Speed is the rate at which an object covers distance, calculated as distance divided by time. It is scalar and measured in meters per second (m/s).

What is velocity?

Velocity is the rate of change of displacement with respect to time, including direction. It is a vector measured in meters per second (m/s).

Define acceleration.

Acceleration is the rate of change of velocity with respect to time, measured in meters per second squared (m/s²).

How do you calculate velocity?

Velocity, v = d / t, where d is displacement and t is time.

How do you calculate acceleration?

Acceleration, a = (v − u) / t, where v is final velocity, u is initial velocity, and t is time.

What is an allele?

An allele is a variant form of a gene that can exist at a specific locus on a chromosome.

Define genotype.

The genotype is the genetic makeup of an organism, specifically the combination of alleles it possesses.

Define phenotype.

The phenotype is the observable physical or biochemical characteristics of an organism, determined by genotype and environment.

What is a dominant allele?

A dominant allele expresses its trait even if only one copy is present (heterozygous condition).

What is a recessive allele?

A recessive allele only expresses its trait when two copies are present (homozygous condition).

What is the difference between homozygous and heterozygous?

Homozygous means having two identical alleles for a gene; heterozygous means having two different alleles.

What are autosomes and sex chromosomes?

Autosomes are chromosomes that do not determine sex; sex chromosomes (e.g., X and Y) determine biological sex.

What is the structure of DNA?

DNA is a double helix composed of nucleotides, each containing a sugar (deoxyribose), phosphate group, and one of four nitrogenous bases (Adenine, Thymine, Cytosine, Guanine).

What was the contribution of Watson, Crick, and Franklin?

Watson and Crick proposed the double helix model of DNA; Franklin's X-ray diffraction images provided critical evidence for this structure.

How does meiosis increase genetic variation?

Meiosis produces gametes with new allele combinations through crossing over and independent assortment, increasing genetic diversity.

Define evolution.

Evolution is the change in inherited characteristics of a population over many generations.

What is natural selection?

Natural selection is the process where individuals with traits better suited to the environment survive and reproduce more successfully, passing those traits on.

What causes genetic variation?

Genetic variation arises from mutations, sexual reproduction (meiosis and fertilisation), and gene flow.

Define mutation.

A mutation is a permanent change in the DNA sequence, which can be beneficial, neutral, or harmful.

What is genetic drift?

Genetic drift is a random change in allele frequencies in a population, especially significant in small populations.

What is gene flow?

Gene flow is the transfer of alleles between populations through migration and interbreeding.

What is isolation in evolution?

Isolation occurs when populations are separated, preventing gene flow, which can lead to speciation.

What is speciation?

Speciation is the process by which new species form when populations become reproductively isolated.

What is a phenotype influenced by?

Phenotype is influenced by both genotype and environmental factors.

What is artificial selection?

Artificial selection is human-directed breeding to produce desired traits in plants or animals.

What is a pedigree?

A pedigree is a diagram showing inheritance patterns of traits across generations.

How do autosomal recessive traits differ from dominant ones in inheritance patterns?

Autosomal recessive traits can skip generations and require two copies of the allele for expression. Dominant traits cannot skip generations and require only one allele.

Define genotype and phenotype.

Genotype: Genetic makeup (e.g., Bb).

Phenotype: Observable trait (e.g., brown eyes).

In pea plants, smooth peas (R) are dominant over wrinkled (r). If two heterozygous plants (Rr) are crossed, what fraction of offspring will have wrinkled peas?

25% (rr).

A heterozygous (Bb) black-furred dog and a homozygous recessive (bb) brown dog mate. What percentage of offspring will be brown?

50% (Bb: black, bb: brown).

In butterflies, blue wings (b) are recessive to black (B). If two heterozygous parents mate, what is the chance of blue offspring?

25% (bb).

If a trait appears in every generation, is it dominant or recessive?

Likely dominant (e.g., autosomal dominant).