AP Biology Unit 2: Cells

Flashcards covering key vocabulary terms and definitions related to cells, their structures, functions, and types, based on AP Biology Unit 2 lecture notes.

Cell

The simplest collection of matter that can be alive; the basic structural and functional units of every organism.

Prokaryotic cells

Cells belonging to the domains bacteria and archaea, characterized by having no nucleus.

Eukaryotic cells

Cells found in protists, fungi, animals, and plants, characterized by having a nucleus and membrane-bound organelles.

Plasma membrane

A boundary that all cells are bound by, regulating what enters and leaves the cell.

Cytosol

A jellylike substance inside the cell in which subcellular components are suspended.

Chromosomes

Structures containing DNA, found within cells.

Ribosomes

Cellular components involved in protein synthesis, found in all cells.

Nucleoid region

The area in the cytoplasm of prokaryotic cells where DNA is located, as there is no nucleus.

Nuclear envelope

A double membrane that surrounds the nucleus in eukaryotic cells.

Surface area to volume ratio

A critical factor for cells; cells must be small to maintain a large ratio, which allows increased rates of chemical exchange.

Villi

Finger-like projections on the small intestine wall that increase surface area for absorption of nutrients.

Microvilli

Projections on each cell of the small intestine that further increase surface area.

Root hairs

Extensions of root epidermal cells in plants that increase surface area for absorbing water and minerals.

Non-membrane bound organelles

Organelles that do not have their own membrane inside the cell, such as ribosomes, cell membrane, cell wall, and cytoplasm.

Membrane-bound organelles

Organelles that have their own membrane inside the cell, such as the nucleus, vacuole, mitochondria, chloroplast, Golgi apparatus, and endoplasmic reticulum.

Compartmentalization

The process by which membrane-bound organelles create different areas in the cell with different conditions, allowing for specialization.

Nucleus

The control center of the cell, containing DNA and mRNA, and surrounded by a double membrane (nuclear envelope).

Nuclear pores

Openings in the nuclear envelope that control what enters and leaves the nucleus.

Chromatin

A complex of DNA and proteins that makes up chromosomes within the nucleus.

Nucleolus

A region within the nucleus where ribosomal subunits (rRNA + proteins) are formed.

Free ribosomes

Ribosomes that float in the cytosol and produce proteins used within the cell.

Bound ribosomes

Ribosomes attached to the Endoplasmic Reticulum that make proteins for export from the cell.

Endomembrane System

A system of membranes including the nuclear envelope, ER, Golgi apparatus, lysosomes, vesicles, vacuoles, and plasma membrane, involved in protein synthesis, transport, lipid metabolism, and detoxification.

Endoplasmic Reticulum (ER)

A network of membranes and sacs within the cell.

Rough ER

A type of ER with ribosomes on its surface, responsible for packaging proteins for secretion, sending transport vesicles to Golgi, and making replacement membrane.

Smooth ER

A type of ER without ribosomes on its surface, responsible for synthesizing lipids and detoxification.

Golgi Apparatus

An organelle consisting of flattened membrane sacs (cisternae) that synthesizes and packages materials for transport in vesicles and produces lysosomes.

Cis face (Golgi)

The receiving side of the Golgi apparatus, where vesicles arrive.

Trans face (Golgi)

The shipping side of the Golgi apparatus, where vesicles depart.

Lysosomes

Membranous sacs containing hydrolytic enzymes, responsible for intracellular digestion, recycling cell materials, and programmed cell death (apoptosis).

Vacuoles

Membrane-bound vesicles used for storage of materials such as food, water, minerals, pigments, and poisons.

Central vacuole

A large vacuole in plant cells that stores water and ions, and retains water for turgor pressure.

Mitochondria

The site of cellular respiration, characterized by a double membrane with inner folds called cristae.

Cristae

Folds of the inner mitochondrial membrane that contain enzymes for ATP production and increase surface area.

Matrix (mitochondrial)

The fluid-filled inner compartment of the mitochondrion.

Chloroplasts

The site of photosynthesis in plant cells, characterized by a double membrane, thylakoid disks in stacks (grana), and stroma.

Thylakoid

Disk-like sacs within chloroplasts where light-dependent reactions of photosynthesis occur.

Grana

Stacks of thylakoids within chloroplasts.

Stroma

The fluid-filled space surrounding the grana within chloroplasts.

Chlorophylls

Pigments contained within chloroplasts that capture sunlight energy for photosynthesis.

Endosymbiont theory

The theory that mitochondria and chloroplasts originated from prokaryotic cells engulfed by ancestors of eukaryotic cells, supported by their double membranes, own ribosomes and DNA, and independent reproduction.

Peroxisomes

Specialized metabolic compartments that break down fatty acids and detoxify alcohol, involving the production of hydrogen peroxide.

Cytoskeleton

A network of protein fibers within the cytoplasm that provides support, aids motility, and regulates biochemical activities.

Microtubules

Components of the cytoskeleton involved in chromosome movements during cell division.

Microfilaments

Components of the cytoskeleton involved in cell division, changes in cell shape, and cell motility.

Intermediate filaments

Components of the cytoskeleton providing anchorage for the nucleus and some other organelles.

Centrosomes

Regions from which microtubules grow, typically containing centrioles in animal cells.

Centrioles

Rod-like structures constructed of microtubules, found at the center of each animal cell centrosome.

Flagella

Long and few appendages that propel cells through water, found in prokaryotes and some eukaryotes.

Cilia

Short and numerous appendages used for locomotion or moving fluids, found in eukaryotes.

9+2 pattern

The arrangement of microtubules in cilia and flagella, consisting of nine outer doublet microtubules surrounding two central single microtubules.

Cell wall

A protective outer layer in plant, fungal, and prokaryotic cells that maintains shape.

Cellulose

The primary component of plant cell walls.

Chitin

The primary component of fungi cell walls.

Peptidoglycan

The primary component of prokaryote cell walls.

Plasmodesmata

Channels between plant cells that allow passage of molecules from cell to cell.

Extracellular Matrix (ECM)

A network of glycoproteins (e.g., collagen) outside the plasma membrane of animal cells that strengthens tissues and transmits external signals.

Tight junctions

Intercellular junctions in animal cells where two cells are fused to form a watertight seal.

Desmosomes

Intercellular junctions in animal cells that act as 'rivets' fastening adjacent cells into strong sheets.

Gap junctions

Intercellular channels in animal cells through which ions, sugar, and small molecules can pass.