Science AT2 Yr 10

Scalar

A quantity with size only (no direction)

Vector

A quantity with both size and direction

Speed

Rate of change of distance over time

Velocity

Speed with a specified direction

Acceleration

The rate of change of speed or velocity over time

Force

A push, pull, or twist that can change speed, shape, or direction

Balanced forces

When opposite forces acting on an object are equal

Unbalanced forces

When opposite forces are not equal, causing a change in motion

Inertia

An object's resistance to changes in motion (Newton's 1st Law)

Newton's 2nd Law

F = ma — force equals mass times acceleration

Newton's 3rd Law

For every action force there is an equal and opposite reaction force on a different object

Heredity

The passing down of traits from parents to offspring

Genetic code

The arrangement of nucleotides providing instructions to grow, live, and reproduce

Genome

The complete set of genetic instructions (all DNA) found in a cell

DNA

Deoxyribonucleic acid — the molecule that carries genetic information, located in the nucleus

Chromosome

A tightly coiled strand of DNA

Gene

A segment of DNA that codes for a specific protein or trait

Nucleotide

The monomer of DNA, made of a sugar, phosphate group, and nitrogenous base

Nitrogenous bases

The four bases in DNA — Adenine, Thymine, Guanine, Cytosine — pairing A–T and C–G

Double helix

The twisted-ladder shape of a DNA molecule

Complementary base pairing

A bonds only with T, and C bonds only with G

RNA

Ribonucleic acid — a single-stranded molecule that helps produce proteins, contains uracil instead of thymine

Uracil

A nitrogenous base found only in RNA, replacing thymine

Amino acids

The monomers that make up proteins

Chargaff's Rules

In DNA, A always equals T and C always equals G

DNA Helicase

The enzyme that unzips DNA by breaking hydrogen bonds between base pairs

DNA Polymerase

The enzyme that builds a new DNA strand by adding complementary nucleotides

DNA Ligase

The enzyme that seals gaps between Okazaki fragments

Okazaki fragments

Short segments of DNA built on the lagging strand during replication

Semi-conservative replication

Each new DNA double helix contains one original strand and one newly built strand

Interphase

The stage before mitosis where the cell grows and DNA replicates

Prophase

Nuclear membrane breaks down, chromatin condenses into chromosomes, spindle fibres form

Metaphase

Chromosomes line up along the cell's equator and spindle fibres attach at the centromere

Anaphase

Spindle fibres pull sister chromatids to opposite poles of the cell

Telophase

Two new nuclei form, chromosomes uncoil, nuclear membrane reappears

Cytokinesis

The cytoplasm splits to produce two separate daughter cells