Year 10 Biology and Physics Review

Flashcards covering Year 10 Genetics (DNA structure, inheritance, and replication) and Physical Sciences (motion, forces, and Newton's Laws).

DNA

Stands for Deoxyribonucleic Acid; it is the body's instruction manual that carries genetic instructions for traits like eye color and blood type.

Nucleus

The organelle in the cell where DNA is found; often described as the "brain" of the cell.

Double Helix

The shape of DNA, which looks like a twisted ladder.

Nucleotide

The repeating building block of DNA, consisting of a deoxyribose sugar, a phosphate group, and a nitrogen base.

Adenine (A)

A nitrogen base in DNA that always pairs with Thymine (T).

Cytosine (C)

A nitrogen base in DNA that always pairs with Guanine (G).

Complementary Base Pairing

The specific matching of DNA bases where $A$ pairs with $T$ and $C$ pairs with $G$.

Gene

A small section of DNA that codes for a specific trait, such as hair texture or eye color.

Chromosome

Tightly coiled or packed bundles of DNA; humans have 46 in total, with 23 inherited from each parent.

DNA Replication

The process of copying DNA before a cell divides to ensure new cells have identical instructions.

Helicase

A helper protein or enzyme that unzips the DNA double helix during replication.

DNA Polymerase

An enzyme that adds matching bases to the exposed DNA strands during replication.

DNA Ligase

An enzyme that acts like glue to join DNA fragments together.

Allele

Different versions of a gene, often represented by letters like $B$ or $b$.

Dominant Allele

A strong allele that is expressed if at least one copy is present, represented by a capital letter.

Recessive Allele

An allele that is hidden unless two lowercase copies are present in the genotype.

Genotype

The specific allele combination or letters an organism has, such as $BB$, $Bb$, or $bb$.

Phenotype

The physical appearance or visible result of the genotype, such as blue eyes.

Homozygous

A genotype consisting of two of the same alleles, like $BB$ (dominant) or $bb$ (recessive).

Heterozygous

A genotype consisting of two different alleles, such as $Bb$.

Punnett Square

A tool used to predict the probability of inheritance for offspring from two parents.

Autosomal Inheritance

The inheritance of traits located on normal chromosomes that affect males and females equally.

Sex-linked Inheritance

The inheritance of traits located on sex chromosomes, usually the $X$ chromosome, which often affects males more frequently.

Pedigree

A genetic family tree using symbols like squares for males and circles for females to track inherited traits.

Scalar Quantity

A physical quantity that has size (magnitude) only and no direction, such as speed, distance, mass, or time.

Vector Quantity

A physical quantity that has both size (magnitude) and direction, such as velocity, displacement, force, or acceleration.

Distance

A scalar quantity reflecting the total path travelled by an object.

Displacement

A vector quantity reflecting the straight-line change from the starting point to the end point, including direction.

Speed

How fast something moves, calculated using the formula $v = \frac{d}{t}$; measured in $m/s$.

Velocity

The speed of an object in a specific direction.

Acceleration

How quickly velocity changes, measured in $m/s^2$ and calculated as $a = \frac{v - u}{t}$.

Newton's First Law (Law of Inertia)

The principle that an object will stay still or keep moving unless an unbalanced force acts on it.

Newton's Second Law

The law stating that bigger force equals bigger acceleration, summarized by the formula $F = ma$.

Newton's Third Law

The principle that every action force has an equal and opposite reaction force.

Meiosis

A type of cell division that produces four non-identical cells (gametes).

Gametes

Sex cells (sperm and egg)

Haploid (n)

A cell with half the number of chromosomes.

Diploid (2n)

A cell with the full set of chromosomes.

Homologous chromosomes

Pairs of chromosomes (one from each parent) that carry the same genes.

Crossing over

When homologous chromosomes swap sections of DNA to increase variation.

Independent assortment

The random way chromosomes are separated into gametes.

Genetic variation

Differences in DNA between individuals.

Fertilissation

When a sperm and egg join to form a new cell.

Zygote

The fertilised egg (diploid cell)

Cell Cycle

The series of stages a cell goes through as it grows and divides.

Mitosis

The process where one cell divides to make two identical daughter cells.

Interphase

The stage before mitosis where the cell grows and copies its DNA.

Chromosome

A structure made of DNA that carries genetic information.

Chromatid

One half of a duplicated chromosome (two identical halves joined together).

Sister Chromatids

The two identical copies of a chromosome joined in the middle.

Centromere

The point where sister chromatids are attached.

Cytokinesis

The process where the cell splits into two identical daughter cells.

Daughter Cells

The two new cells formed after mitosis, which are genetically identical.

Nucleus

The part of the cell that contains the DNA.

Spindle Fibres

Thin structures that pull sister chromatids apart during mitosis.

Prophase

The stage of mitosis where chromosomes become visible and the nucleus starts to break down.

Metaphase

The stage of mitosis where chromosomes line up in the middle of the cell.

Anaphase

The stage of mitosis where sister chromatids are pulled apart to opposite sides of the cell.

Telophase

The stage of mitosis where new nuclei form around each set of chromosomes.

Prophase I

Homologous chromosomes pair up and crossing over occurs. 

Metaphase I

Chromosome pairs line up in the middle. 

Anaphase I

Homologous chromosomes are pulled apart. 

Telophase I

Two cells form, each with half the chromosomes. 

Prophase II

Chromosomes become visible again. 

Metaphase II

Chromosomes line up in the middle. 

Anaphase II

Sister chromatids are pulled apart.

Telophase II

Four haploid cells are formed.