Bio Chem and Physics test

Atomic Number

The number of protons in an atom.

Atomic Mass

The total number of protons and neutrons in an atom.

Groups on the Periodic Table

Columns that indicate the number of valence electrons and similar chemical properties.

Periods on the Periodic Table

Rows that indicate the number of electron shells.

Atomic Radius Down a Group

Increases as more electron shells are added.

Reactivity of Group 1 Alkali Metals

Highly reactive due to one easily lost valence electron.

Atomic Radius and Reactivity in Metals

Larger atomic radius = easier to lose electrons = more reactive.

Ionic Bonding

The transfer of electrons from a metal to a non-metal, forming oppositely charged ions.

Covalent Bonding

The sharing of valence electrons between two non-metals.

Polar Covalent Bond

A bond with unequal sharing of electrons, e.g., H₂O.

Non-Polar Covalent Bond

A bond with equal sharing of electrons, e.g., O₂.

Ionic Compounds Melting Points

High melting points due to strong electrostatic attractions between ions.

Covalent Compounds Melting Points

Low melting points due to weak forces between molecules.

Lewis Dot Diagram

A representation showing only valence electrons as dots around a chemical symbol.

Bohr Diagram

A representation showing all electron shells around an atomic nucleus.

Chromosomes Composition

Made of DNA tightly coiled around histone proteins.

Chromatin

Uncoiled DNA present in the nucleus when the cell is not dividing.

Gene

A segment of DNA that codes for a specific protein.

Sister Chromatids

Identical copies of a chromosome, joined at the centromere.

Human Chromosome Count

Humans have 46 chromosomes, organized as 23 pairs; gametes have 23.

Karyotype

A visual representation of chromosomes arranged by size and shape used to identify abnormalities.

Purpose of Mitosis

To facilitate growth, repair, and asexual reproduction.

Cells Produced by Mitosis

Two identical diploid cells.

Prophase in Mitosis

Chromatin condenses, spindle fibers form, and the nuclear membrane dissolves.

Metaphase in Mitosis

Chromosomes align at the center of the cell, and spindle fibers attach to centromeres.

Anaphase in Mitosis

Spindle fibers pull sister chromatids to opposite poles.

Telophase in Mitosis

The nuclear membrane reforms, and chromatids uncoil.

Cytokinesis

The process of dividing the cytoplasm into two identical cells.

Purpose of Meiosis

To produce four unique haploid gametes for sexual reproduction.

Prophase I of Meiosis

Chromosomes pair up, and crossing over occurs.

Crossing Over

The exchange of DNA between homologous chromosomes for increased genetic diversity.

Independent Assortment

The random arrangement of homologous chromosome pairs during Metaphase I.

Meiosis II Comparison to Mitosis

Meiosis II separates sister chromatids, similar to mitosis.

End Result of Meiosis

Four genetically different haploid cells.

Allele

A different version of a gene.

Dominant Allele

An allele that masks the effect of a recessive allele.

Recessive Allele

An allele that is expressed only when both alleles are recessive.

Genotype

The genetic makeup of an organism (e.g., Bb, BB, bb).

Phenotype

The observable physical traits expressed by an organism.

Homozygous

Having two identical alleles (e.g., BB or bb).

Heterozygous

Having two different alleles (e.g., Bb).

Punnett Square

A tool used to predict the genotype and phenotype ratios of offspring.

X-Linked Traits in Males

Males are more affected by X-linked traits due to having only one X chromosome.

Distance vs. Displacement

Distance measures total path traveled; displacement measures the straight line from start to end with direction.

Scalar Quantity

A quantity that has magnitude only, such as speed or distance.

Vector Quantity

A quantity that has both magnitude and direction, such as velocity or displacement.

Formula for Speed

Speed equals distance divided by time.

Formula for Velocity

Velocity equals displacement divided by time.

Flat Line on a Distance-Time Graph

Indicates the object is stationary.

Steeper Slope on a Distance-Time Graph

Indicates higher speed.

Downward Slope on a Displacement-Time Graph

Indicates the object is moving back or in the opposite direction.

Area Under a Velocity-Time Graph

Represents the displacement of the object.

Slope of a Velocity-Time Graph

Represents acceleration.