bio unit 1 flashcards

human body organization

Cells → Tissues → Organs → Organ Systems → Organism.

common cell structures

Plasma membrane, cytoplasm, ribosomes, and genetic material (DNA/RNA).

prokaryote

no nucleus (nucleoid region), DNA free floating, smaller simpler, ex: bacteria

eukaryote

has a nucleus, membrane-bound organelles, larger, more complex; example: plants, animals, fungi, protists

primary function of plasma membrane

To regulate what enters and leaves the cell, maintaining homeostasis.

macromolecules

Carbohydrates, lipids, proteins, nucleic acids.

example of each macromolecule:

Carbs: glucose; Lipids: fats/oils; Proteins: enzymes; Nucleic acids: DNA/RNA.

function of carbohydrates

Provide energy and structural support.

function of proteins

Catalyze reactions (enzymes), transport, structural support, communication.

functions of lipids

Store energy, form membranes, act as signaling molecules, hormones

function of nucleic acids

Store and transmit genetic information.

catabolic reactions

A: Molecules are broken down, releasing energy

anabolic reactions

molecules are built up, requiring energy

hydrolysis

water is used to break bonds in molecules

dehydration synthesis

water is removed to form new bonds between molecules

atomic structure

Atoms consist of protons, neutrons, and electrons; bonds form when atoms share or transfer electrons.

function of plasma membrane

To regulate entry/exit of substances and protect the cell.

function of phospholipids

Form a bilayer with hydrophilic heads and hydrophobic tails, creating a barrier.

function of transport proteins

Facilitate movement of molecules across the membrane.

fatty acid tails

hydrophobic

phosphate heads

hydrophilic

molecules diffusible across plasma membrane

small, non polar, uncharged molecules: O2, CO2 (gases)

molecules can’t diffuse across plasma membrane

Large, polar, hydrophilic or charged molecules (e.g., glucose, ions).

concentration gradient

The difference in concentration of a substance across a space.

way molecules move through concentration gradient

From high concentration to low concentration (into or out of cell depending on gradient).

Why is active transport important to cells?

Maintains concentration differences essential for processes like nerve signaling and nutrient uptake.

diffusion

Movement of particles from high concentration to low concentration.

simple diffusion

Small, nonpolar molecules pass directly through the membrane (no proteins needed).

facilitated diffusion

Molecules move through transport proteins in the membrane (no energy needed)

osmosis

Movement of water across a membrane from low solute to high solute.

primary active trasnport

uses ATP to move molecules against the gradient.

secondary active transport

Uses energy from another gradient to move molecules.

organelle only in plant cells

Cell wall, chloroplasts, large central vacuole.

organelle only in animal cells

centrioles/ centrosomes, lysosomes

eukaryotic cell vs prokaryotic cell

Eukaryotic cells have a nucleus and membrane-bound organelles; prokaryotes do not.

endomembrane system pathway

DNA (in Nucleus) → mRNA → Nuclear Membrane (pore exit) → Ribosome (builds amino acids into protein) → Rough ER (protein folding/mods) → Transport Vesicle → Golgi Apparatus (processing/packaging) → Secretory Vesicle → Plasma Membrane (release or embed protein)

ribosomes

Function: Synthesizes proteins; Location: Free in cytoplasm or on rough ER; Cell type: Both

nucleolus

Function: Produces ribosomal RNA and assembles ribosome subunits; Location: Inside the nucleus; Cell type: Both

nucleus

Function: Controls cell activities, stores DNA; Location: Center of the cell; Cell type: Both

plasma membrane

Function: Regulates what enters and exits the cell, protects the cell, communicates with environment; Location: Surrounds cell; Cell type: Both

vesicle

Function: Transports and stores substances within the cell, aids in secretion; Location: Cytoplasm; Cell type: Both

rough ER

Function: Synthesizes and folds proteins for export or membranes; Location: Near nucleus, connected to nuclear envelope; Cell type: Both

smooth ER

Function: Synthesizes lipids and steroids, detoxifies chemicals; Location: Cytoplasm, connected to rough ER; Cell type: Both

Golgi apparatus

Function: Modifies, sorts, and packages proteins and lipids; Location: Cytoplasm near ER; Cell type: Both

mitochondria

Function: Produces ATP via cellular respiration, regulates metabolism; Location: Cytoplasm; Cell type: Both

flagella

Function: Enables cell movement; Location: Extends from cell surface; Cell type: Mostly animal, some bacteria and protists

vacuole

Function: Stores water, nutrients, and waste; maintains turgor pressure in plants; Location: Cytoplasm; Cell type: Both (large in plants, small in animals)

cell wall

Function: Provides structure and protection; Location: Outside plasma membrane; Cell type: Plant (also fungi and bacteria)

lysosome

Function: Digests macromolecules, pathogens, and waste; Location: Cytoplasm; Cell type: Mostly animal, rare in plants

chloroplasts

Function: Photosynthesis; Location: Cytoplasm; Cell type: Plant and algae

cytoskeleton

Function: Supports cell shape, moves organelles and vesicles; Location: Cytoplasm; Cell type: Both

cilia

Function: Moves fluids over cell surface or aids locomotion; Location: Cell surface; Cell type: Mostly animal, some protists