MCAT Biology Review: The Cell and Reproduction

Vocabulary flashcards covering the cell theory, eukaryotic and prokaryotic structures, cellular genetics, viruses, and the human reproductive system based on MCAT prep material.

Cell Theory Tenet 1

All living things are composed of cells.

Cell Theory Tenet 2

The cell is the basic functional unit of life.

Cell Theory Tenet 3

Cells arise only from preexisting cells.

Cell Theory Tenet 4

Cells carry genetic information in the form of deoxyribonucleic acid ($DNA$).

Robert Hooke

Scientist who observed honeycomb-like structures in cork in $1665$ and coined the term cells.

Anton van Leeuwenhoek

The first person to view a living cell under a microscope in $1674$.

Rudolph Virchow

Demonstrated in $1850$ that diseased cells could arise from normal cells in normal tissues.

Viruses and Cell Theory Violation 3

Viruses violate the third tenet because they can only replicate by invading other organisms.

Viruses and Cell Theory Violation 4

Viruses violate the fourth tenet because they may use ribonucleic acid ($RNA$) as their genetic information.

Eukaryotic cells

Organisms that contain a true nucleus enclosed in a membrane.

Prokaryotic cells

Single-celled organisms that do not contain a nucleus.

Cytosol

The semifluid in which organelles are suspended within the cell.

Phospholipid bilayer

The structure of eukaryotic membranes with hydrophilic surfaces and a hydrophobic inner portion.

Hydrophilic surface

The part of the cell membrane that electrostatically interacts with aqueous environments.

Hydrophobic inner portion

The part of the cell membrane that provides a selective barrier against the external environment.

Nucleus

The control center of the cell containing genetic material necessary for replication.

Nuclear membrane

A double membrane that separates the nuclear environment from the cytoplasm; also called the nuclear envelope.

Nuclear pores

Openings in the nuclear membrane allowing selective two-way exchange of material.

Genes

Coding regions within the genetic material ($DNA$).

Histones

Organizing proteins around which linear $DNA$ is wound.

Chromosomes

Linear strands of $DNA$ formed from wound histones.

Nucleolus

Subsection of the nucleus where Ribosomal $RNA$ ($rRNA$) is synthesized.

Mitochondria

The power plants of the cell; metabolic centers containing an outer and inner membrane.

Mitochondrial outer membrane

A barrier between the cytosol and the inner environment of the mitochondrion.

Cristae

Infoldings of the inner mitochondrial membrane that increase surface area for electron transport chain enzymes.

Intermembrane space

The space between the inner and outer mitochondrial membranes.

Mitochondrial matrix

The space inside the inner mitochondrial membrane.

Proton-motive force

Established by pumping protons from the mitochondrial matrix to the intermembrane space.

Mitochondrial replication

Mitochondria contain their own genes and replicate independently via binary fission.

Cytoplasmic inheritance

Transmission of genetic material independent of the nucleus; also known as extranuclear inheritance.

Apoptosis

Programmed cell death, which can be triggered by the release of mitochondrial enzymes.

Lysosomes

Membrane-bound structures containing hydrolytic enzymes for breaking down substrates.

Endosomes

Structures that transport, package, and sort cell material traveling to and from the membrane.

Autolysis

The process where lysosomes release enzymes, leading to the degradation of cellular components.

Endoplasmic Reticulum ($ER$)

Interconnected membranes contiguous with the nuclear envelope with a central lumen.

Rough Endoplasmic Reticulum ($RER$)

$ER$ studded with ribosomes for translation of proteins destined for secretion.

Smooth Endoplasmic Reticulum ($SER$)

$ER$ primarily used for lipid synthesis and detoxification of drugs and poisons.

Golgi apparatus

Stacked membrane-bound sacs that modify, sort, and repackage cellular products from the $ER$.

Exocytosis

Process by which secretory vesicles merge with the cell membrane to release contents.

Peroxisomes

Organelles containing hydrogen peroxide used to break down very long chain fatty acids.

$\beta$-oxidation

The process used by peroxisomes to break down fatty acids.

Cytoskeleton

Structure providing shape to the cell and a conduit for material transport.

Microfilaments

Solid polymerized rods of actin that provide protection and aid in cytokinesis.

Actin

The protein that makes up microfilaments.

Myosin

Protein that interacts with actin to generate force for movement, such as muscle contraction.

Cleavage furrow

Formed from microfilaments during mitosis to pinch off the connection between daughter cells.

Microtubules

Hollow polymers of tubulin proteins that provide pathways for motor proteins.

Tubulin

The protein that makes up microtubules.

Kinesin

A motor protein that travels along microtubules.

Dynein

A motor protein that travels along microtubules.

Cilia

Microtubule projections involved in moving materials along the surface of the cell.

Flagella (Eukaryotic)

Microtubule structures involved in the movement of the cell itself.

$9 + 2$ structure

The arrangement of nine pairs of microtubules in an outer ring with two in the center.

Centrioles

Organizing centers for microtubules located in the centrosome.

Centrosome

Region of the cell containing centrioles.

Kinetochores

Complexes on chromosomes where microtubules from centrioles attach.

Intermediate Filaments

Diverse group of filamentous proteins involved in cell-cell adhesion and structural rigidity.

Keratin

An example of an intermediate filament protein.

Desmin

An example of an intermediate filament protein.

Vimentin

An example of an intermediate filament protein.

Lamins

An example of an intermediate filament protein.

Parenchyma

The functional parts of an organ, often composed of epithelial cells.

Epithelial tissues

Tissues covering the body and lining cavities for protection, absorption, and secretion.

Basement membrane

An underlying layer of connective tissue to which epithelial cells are tightly joined.

Polarized cells

Cells where one side faces a lumen or the outside world, while the other interacts with vessel/support cells.

Simple epithelia

Epithelial tissue with one layer of cells.

Stratified epithelia

Epithelial tissue with multiple layers of cells.

Pseudostratified epithelia

Epithelial tissue that appears to have multiple layers due to cell height differences but is only one layer.

Cuboidal cells

Cube-shaped epithelial cells.

Columnar cells

Long and thin epithelial cells.

Squamous cells

Flat and scale-like epithelial cells.

Connective tissue

Supports the body and provides a framework for epithelial cells; contributes to the stroma.

Stroma

The support structure of an organ.

Extracellular matrix

Formed by secretions of collagen and elastin from connective tissue cells.

Nucleoid region

Area in a prokaryotic cell where the single circular molecule of $DNA$ is concentrated.

Archaea

Single-celled organisms visually similar to bacteria but with metabolic pathways similar to eukaryotes.

Extremophiles

Organisms isolated from harsh environments like high temperature or high salinity.

Chemosynthesis

Generating energy from inorganic compounds like sulfur- or nitrogen-based compounds.

Bacteria

Domain containing cell membrane, cytoplasm, and often flagella or fimbriae.

Mutualistic symbiotes

Relationship where both the human host and bacteria benefit.

Pathogens

Bacteria that provide no benefit to the host and cause disease.

Cocci

Spherical-shaped bacteria.

Bacilli

Rod-shaped bacteria.

Spirilli

Spiral-shaped bacteria.

Obligate aerobes

Bacteria that require oxygen for metabolism.

Anaerobes

Bacteria that use fermentation or metabolism not requiring oxygen.

Obligate anaerobes

Anaerobes that cannot survive in an oxygen-containing environment.

Facultative anaerobes

Bacteria that can switch between aerobic and anaerobic metabolism.

Aerotolerant anaerobes

Bacteria unable to use oxygen for metabolism but not harmed by its presence.

Envelope (Prokaryotic)

Term for the combination of the cell wall and cell membrane.

Gram staining

Process using crystal violet and safranin to classify bacterial cell walls.

Gram-positive

Bacteria that appear deep purple after staining; possess thick peptidoglycan layers.

Gram-negative

Bacteria that appear pink-red after staining; possess thin peptidoglycan and an outer membrane.

Peptidoglycan

Polymeric substance made from amino acids and sugars in bacterial cell walls.

Lipoteichoic acid

Chemical in gram-positive cell walls that may activate the human immune system.

Periplasmic space

The space between the gram-negative cell wall and the cell membrane.

Lipopolysaccharides

Part of gram-negative outer membranes that triggers a strong inflammatory response in humans.

Chemotaxis

The ability of a cell to detect and move toward or away from chemical stimuli.

Filament (Flagella)

Hollow, helical structure composed of flagellin in bacterial flagella.

Basal body

Motor of the flagellum that anchors it to the cytoplasmic membrane.