College Entrance Exam: Biology & Physics Test Secrets Study Guide Flashcards

A comprehensive set of vocabulary flashcards covering the key concepts in Biology and Physics as presented in the PTS Tutorial and Review Systems study guide.

Cell Theory

The theory stating that the cell is life's basic unit of structure and function and the smallest unit of living material that can carry out all activities necessary for life.

Light Microscope

Also known as compound microscopes, these are used to study stained or living cells and can magnify organisms up to $1,000$ times.

Electron Microscope

A microscope used to study the detailed structure of a cell, capable of magnifying up to $250,000$ times, though it can only observe killed cells.

Eukaryotic Cell

A type of cell that contains a membrane-bound nucleus and cytoplasm filled with organelles; examples include fungi, protists, plant cells, and animal cells.

Prokaryotic Cell

A cell that lacks a nucleus and membrane-bound organelles; its genetic material is one continuous, circular DNA molecule located in the nucleoid.

Organelles

Literally meaning 'little organs,' these are tiny structures within the cytoplasm of eukaryotic cells that perform special tasks.

Plasma Membrane

A complex double-layered structure made of phospholipids and proteins that regulates the movement of substances into and out of the cell.

Nucleolus

The structure within the nucleus where rRNA is made and ribosomes are assembled.

Ribosomes

The sites of protein synthesis composed of RNA and proteins; they can be free-floating or attached to the endoplasmic reticulum.

Endoplasmic Reticulum (ER)

A continuous channel in the cytoplasm; the 'rough' version is studded with ribosomes for protein export, while the 'smooth' version makes lipids and hormones.

Golgi Bodies

Stacks of flattened sacs that modify, process, and sort protein products before packaging them into vesicles for distribution.

Mitochondria

Often called the 'powerhouses' of the cell, these organelles convert energy from organic molecules into adenosine triphosphate ($ATP$).

Lysosomes

Small, membrane-bound sacs carrying digestive enzymes used to break down debris and old organelles; they serve as the cell's cleanup crew.

Centrioles

Paired, cylindrical structures found in animal cells that produce microtubules to pull replicated chromosomes apart during cell division.

Cytoskeleton

A network of fibers, including microtubules and microfilaments, that determines the shape of a cell and enables its movement.

Catabolism

The metabolic process by which the cell breaks down complex molecules to produce energy and reducing power.

Anabolism

The metabolic process by which the cell constructs complex molecules and performs other biological functions.

First Law of Thermodynamics

The principle that energy cannot be created or destroyed; the sum of energy in the universe is constant.

Second Law of Thermodynamics

The principle that energy transfer leads to less organization, meaning the universe tends toward disorder or entropy.

Adenosine Triphosphate ($ATP$)

The primary energy molecule of the cell, consisting of adenosine bonded to three phosphates.

Photosynthesis

The process of transforming solar energy into chemical energy, consisting of light-dependent and light-independent (dark) reactions.

Aerobic Respiration

Cellular respiration that occurs in the presence of oxygen to produce $ATP$.

Anaerobic Respiration

The production of $ATP$ without oxygen; in humans, pyruvic acid from glycolysis is converted to lactic acid.

DNA (Deoxyribonucleic Acid)

The hereditary blueprint of the cell, organized into segments called genes on chromosomes; it exists as a double helix deduced by Watson and Crick in 1956.

Transcription

The process by which genetic information is transferred from DNA to RNA in the nucleus.

Translation

The process by which RNA in the cytoplasm is used to produce proteins.

Interphase

The 'resting stage' or growing phase in the cell cycle during which the cell produces proteins and enzymes needed to grow and carries out regular activities.

Mitosis

The period when the cell divides into two identical daughter cells; stages include prophase, metaphase, anaphase, and telophase.

Diploid Cell

A cell that has two full sets of chromosomes, represented as $2n$; in humans, the diploid number is $46$.

Haploid Cell

A cell that has only one set of chromosomes, represented as $n$; in humans, the haploid number is $23$, found in gametes.

Meiosis

The production of gametes by germ cells in the gonads (testes or ovaries), involving two rounds of division to produce four haploid cells.

Gametogenesis

The process of producing sperm (spermatogenesis) or eggs (oogenesis) through meiosis.

Genetics

The study of heredity, explaining how characteristics are passed from parents to children.

Alleles

Alternate forms of the same gene, such as an allele for 'tall' and an allele for 'short' in pea plants.

Homozygous

An organism that has two identical alleles for a given trait (e.g., $TT$ or $tt$).

Heterozygous

An organism that has two different alleles for a given trait (e.g., $Tt$).

Phenotype

The physical appearance or expressed characteristic of an organism.

Genotype

The genetic makeup of an organism, identifying which alleles it possesses.

Law of Dominance

Mendel's principle stating that one trait (dominant) can mask the effect of another trait (recessive).

Law of Segregation

Mendel's principle stating that alleles separate and recombine during the formation of offspring.

Law of Independent Assortment

Mendel's principle stating that traits segregate and recombine independently of other traits.

Incomplete Dominance

A pattern of inheritance where traits blend, such as a white snapdragon and a red snapdragon producing pink progeny.

Codominance

A pattern of inheritance involving the equal expression of both alleles, such as the $AB$ blood type.

Taxonomy

The science of classifying animals according to their phylogeny or evolutionary relatedness.

Binomial Classification System

Developed by Carolus Linnaeus, it assigns scientific names consisting of a genus and a species name.

Phylogeny

The sum of traits manifested in organisms that reflect their evolutionary relations.

Cephalization

The tendency in bilaterally symmetrical animals for sensory and neural organs to concentrate at the anterior end, leading to brain development.

Xylem

Plant tissue that conducts water and minerals upward from the roots.

Phloem

Plant vessels that carry nutrients, such as glucose, throughout the plant.

Auxins

The major class of plant hormones involved in phototropism, cell elongation, and fruit development.

Digestion

The breakdown of large food molecules into simpler compounds that the body can absorb.

Peristalsis

The wavelike motion that moves food through the esophagus to the stomach.

Villi

Fingerlike projections in the small intestine that increase surface area for food absorption.

Alveolus

The tiny air sac at the end of a bronchiole where gas exchange between the lung and capillaries occurs via passive diffusion.

Systemic Circulation

The path of blood from the left ventricle through the body to the right atrium.

Pulmonary Circulation

The path of blood from the right ventricle to the lungs to pick up oxygen and return to the left atrium.

Natural Selection

The theory developed by Charles Darwin stating that nature chooses survivors based on their fitness; 'survival of the fittest.'

Homologous Structures

Similar anatomical structures in different animals that serve different functions but point to a common ancestor (e.g., human arm and whale fin).

Analogous Structures

Features with the same function but different structural origins (e.g., bat wing and insect wing).

Speciation

The emergence of new species, which can be allopatric (geographic barrier) or sympatric (no barrier).

Instinct

An inborn, unlearned behavior that acts as inherited 'circuitry' to guide an organism's behavior.

Imprinting

A form of learning occurring during a brief, critical period early in life that helps organisms recognize members of their own species.

Biosphere

The entire part of the earth where living things exist, including soil, water, light, and air.

Niche

An organism's specific position or function within a community.

Newtonian Mechanics

The subdivision of Physics that studies the effects of forces on bodies.

Scalar

A quantity characterized by a magnitude (positive or negative number) without direction, such as mass or time.

Vector

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

First Law of Motion (Law of Inertia)

Newton's law stating that a body at rest stays at rest and a body in motion stays in motion unless acted upon by an external force.

Second Law of Motion (Law of Acceleration)

Newton's law stating that net force is equal to mass multiplied by acceleration, expressed as $\mathbf{F} = m\mathbf{a}$.

Third Law of Motion (Law of Action-Reaction)

Newton's law stating that for every action, there is an equal but opposite reaction.

Momentum

Defined as 'mass in motion,' it is calculated as the product of mass and velocity ($p = m v$).

Work

The activity involving a force causing movement in the direction of that force, measured in Joules ($J$).

Energy

The capacity for doing work, existing as kinetic (motion) or potential (position).

Power

The rate at which work is done or energy is used, calculated as $\frac{\text{Work}}{\text{time}}$ and measured in Watts ($W$).