Big Ideas in Science: Space Science and the Mystery of Life Revision

Comprehensive vocabulary flashcards covering Unit 3 (Space Science: The Universe, Big Bang Theory, Star Formation, and Data Analysis) and Unit 4 (The Mystery of Life: DNA Structure, Mitosis, Meiosis, Mendelian Genetics, Pedigree Charts, Karyotyping, Gene Therapy, and Evolution by Natural Selection).

Universe

All of space, time, matter, and energy that exists everywhere, including all planets, stars, and galaxies.

Theorised Age of the Universe

Around $13.8\text{ billion}$ years old.

Galaxy

A huge collection of billions of stars, gas, and dust held together by gravity.

Star

A glowing ball of hot gas that makes its own heat and light through nuclear reactions in its core.

Planet

A round body in space that orbits a star and has cleared its path of other large rocks.

Celestial Body

Any natural object found out in space, like a moon, planet, asteroid, or comet.

Nebula

A giant cloud of dust and gas floating in space where new stars are born.

Black Hole

A place in space where gravity is so strong that nothing, not even light, can escape.

Constellation

A recognizable pattern or picture made by a group of stars in the night sky.

Astronomical Unit (AU)

The average distance between Earth and the Sun, used to measure distances inside our solar system.

Light-Year

The distance light travels in one full year, used to measure huge distances between stars and galaxies.

Big Bang Theory

The scientific idea that the universe started as an extremely tiny, hot, dense point that suddenly expanded outward and is still stretching today.

Three Pieces of Evidence for the Big Bang Theory

The large amounts of light elements (hydrogen and helium), the leftover cosmic microwave background glow, and the redshift of distant galaxies.

Cosmic Microwave Background (CMB) Radiation

Faint leftover heat energy from shortly after the start of the universe that still fills all of space.

Redshift

The stretching of light waves toward longer, red wavelengths as an object moves away from us in space.

Redshift vs. Blueshift

Redshift means an object is moving away because its light waves stretch out, while blueshift means an object is moving closer because its light waves bunch together.

Hubble's Law

The rule that galaxies that are farther away from us are moving away faster than closer galaxies.

How to Identify Redshift in Spectral Data

Look at the dark absorption lines in the light pattern; if they have slid toward the red side compared to resting light, redshift has occurred.

How to Find Star Temperature on a Planck Curve

Find the peak of the curve; a taller peak shifted toward shorter wavelengths (blue light) means the star is hotter.

How to Find Absolute Magnitude on an H-R Diagram

Read the vertical axis to find the true brightness of a star based on where it sits on the chart.

Factors Determining the Fate of a Star

Starting mass, surface temperature, total age, and how quickly it burns up its hydrogen fuel.

Nuclear Fusion

The process where atomic nuclei smash together under extreme heat and pressure to make heavier nuclei and release huge amounts of energy.

Life Cycle of an Average-Sized Star

Begins in a nebula, becomes a protostar, lives as a main sequence star, expands into a red giant, puffs away a planetary nebula, and leaves behind a cooling white dwarf.

Life Cycle of a Massive Star

Begins in a nebula, lives as a heavy main sequence star, expands into a red supergiant, explodes in a supernova, and collapses into a neutron star or black hole.

Full Name of DNA

Deoxyribonucleic acid.

Location of DNA in Cells

Inside the cell nucleus, packaged tightly into structures called chromosomes.

Shape of DNA

A twisted ladder shape called a double helix.

What DNA is Made Up Of

Repeating units called nucleotides, consisting of a sugar-phosphate backbone (deoxyribose sugar and phosphate) and rungs made of paired nitrogenous bases.

Three Parts of a Nucleotide

A phosphate group, a deoxyribose sugar molecule, and a nitrogenous base.

Four Nitrogenous Bases in DNA and Their Pairs

Adenine ($A$) pairs with thymine ($T$), and cytosine ($C$) pairs with guanine ($G$).

Helicase

The enzyme that unwinds the double helix and unzips the base pairs before DNA replication begins.

Gene

A short segment of DNA on a chromosome that holds the instructions to make a protein for a specific trait.

Genome

The complete set of all genetic instructions and DNA found inside an organism.

Purpose and Outcome of Mitosis

Used for growth and repair in somatic (body) cells, producing $2$ genetically identical daughter cells.

Purpose and Outcome of Meiosis

Used to make sex cells (gametes) in germ cells for sexual reproduction, producing $4$ genetically unique daughter cells with half the chromosome count.

Diploid vs. Haploid Cells

Diploid ($2n$) cells have two complete sets of chromosomes (like body cells), while haploid ($n$) cells have only one single set (like sperm and egg cells).

Stages of Mitosis

Interphase (growth and DNA copy), followed by Prophase, Metaphase, Anaphase, Telophase, and Cytokinesis.

Stages of Meiosis

Interphase, followed by Meiosis I (Prophase I, Metaphase I, Anaphase I, Telophase I, Cytokinesis) and Meiosis II (Prophase II, Metaphase II, Anaphase II, Telophase II, Cytokinesis).

Crossing Over in Meiosis

The process during Prophase I where matching chromosomes swap pieces of genetic material to create variation in gametes.

Genetics

The scientific study of how traits and characteristics are passed down from parents to offspring.

Inherited Trait vs. Acquired Trait

An inherited trait is passed down through DNA code from parents (like eye color), while an acquired trait is a skill or feature learned during life (like speaking a language).

Allele

Different versions or variations of the same gene.

Dominant Allele

A stronger gene version that always shows up if it is present, written with a capital letter.

Recessive Allele

A hidden gene version that only shows up when no dominant version is present, written with a lowercase letter.

Homozygous

Having two identical alleles for a trait, such as $TT$ or $tt$.

Heterozygous

Having two different alleles for a trait, such as $Tt$.

Genotype

The specific combination of alleles an organism inherits, written with letter pairs like $BB$, $Bb$, or $bb$.

Phenotype

The physical appearance or observable characteristic of an organism that can be seen.

Punnett Square

A simple grid used to predict the possible allele combinations and physical traits of offspring.

Pedigree Chart Symbols

Squares represent males, circles represent females, horizontal lines show mating, vertical lines lead to children, and shaded shapes mean the person has the trait.

Identifying a Dominant Trait on a Pedigree Chart

Look for a trait that appears in every single generation without skipping, where every affected child has an affected parent.

Identifying a Recessive Trait on a Pedigree Chart

Look for a trait that skips generations, where two unaffected carrier parents ($Bb$) have an affected child ($bb$).

Predicting Genotypes on a Pedigree Chart

Individuals showing a recessive trait must be $bb$, and unaffected parents who produce an affected child must be carriers ($Bb$).

Karyotyping

The process of taking photos of chromosomes during metaphase and sorting them by size and pattern to check for missing, extra, or damaged chromosomes.

SHE: Role of Science in Karyotyping

Science explains how chromosomes work and how cell division mistakes in meiosis cause disorders like Down syndrome.

SHE: Role of Technology in Karyotyping

Technology creates chemical stains to make chromosome bands visible, along with digital cameras and imaging software to capture clear photos.

SHE: Role of Engineering in Karyotyping

Engineering builds and improves high-power microscopes and automated slide scanners that scan samples quickly and accurately.

Gene Therapy

A medical method that treats genetic diseases by replacing a faulty gene, turning off a harmful gene, or adding a healthy new gene into cells.

Four Steps of Gene Therapy

1. Identify the faulty mutated gene; 2. Build a healthy copy of the gene; 3. Pick a delivery tool (like a harmless virus); 4. Deliver the gene into the patient's cells.

SHE: Role of Science in Gene Therapy

Science discovers which genes cause diseases and studies how DNA mutations affect normal body functions.

SHE: Role of Technology in Gene Therapy

Technology provides DNA-editing tools and safely modifies viruses into vectors that can carry healthy genes into target cells.

SHE: Role of Engineering in Gene Therapy

Engineering designs physical delivery systems and builds automated laboratory machines that insert DNA into cells at scale.

Evolution

The gradual change in the inherited characteristics of a population over many generations.

Significance of Evolution in Biology

It explains the variety of living things, how organisms adapt to their surroundings, and how all species connect to common ancestors.

Darwin's Theory vs. Lamarck's Theory

Darwin argued that helpful natural variations help organisms survive and reproduce, whereas Lamarck wrongly claimed that body parts changed during an animal's life are passed on to offspring.

Natural Selection

The main driving force of evolution where the environment favors individuals with helpful traits, helping them survive and reproduce.

Three Steps of Natural Selection

1. Variation (natural differences exist in a population); 2. Isolation (groups get split by barriers); 3. Selection (environmental pressures favor the most helpful traits).

Speciation

The formation of new, separate species when an isolated population changes so much over time that it can no longer breed with the original group.

Structural Adaptation vs. Behavioural Adaptation

A structural adaptation is a physical body part (like webbed feet or thick fur), while a behavioural adaptation is an action or habit (like hibernating or migrating).

Natural Selection vs. Artificial Selection

Natural selection is nature favoring traits that help an organism survive in the wild, while artificial selection is humans choosing and breeding organisms for specific traits.

Four Lines of Evidence Supporting Evolution

Fossil records in rock layers, chemical and anatomical similarities, geographic distribution of species, and similarities in early embryos.

Homologous Structures

Body parts in different animals that share a similar bone layout from a common ancestor, even if they are used for different jobs (like a human arm and a bat wing).