BIO198 - Unit 2 Exam

Structure-function relationships

molecules, cells, tissues, and organs depends upon their structure

Transform energy and matter

constantly breaking down "food" molecules for energy; use energy to build other complex molecules

Extracellular matrix

solutes that are outside the membrane; found between cells within tissues

ECM made from

proteins, carbohydrates

ECM function

link cells to each other within tissues

Plasma membrane

surrounds the cell and separates organelles (eukaryotic cells) from the exterior environment

plasma membrane made from

lipids - phospholipids and cholesterol

Lipid representations

phospholipids (most abundant component) AND cholesterol

Lipid functions for cell membrane

interact with both the water interior of cells and watery solution outside of cells as components of the cell membrane

Membrane proteins

embedded or on 1 side of the plasma membrane

Membrane protein functions

transporters, cell-to-cell adhesion, attachment to cytoskeleton

Cell membrane function

facilitate the transport of ions and other solutes; various type of membrane transport that occurs with or without transmembrane proteins

Selective permeability (of the cell membrane)

allows only solutes meeting certain criteria to pass through it unaided

Easily move through lipid bilayer

small, nonpolar materials; lipids, oxygen, and carbon dioxide gases, and alcohol

Water soluble materials

(glucose, amino acids, electrolytes) need some assistance to cross the membrane because they are repelled by the hydrophobic tails of the phospholipid bilayer

Passive transport

movement of solutes without the expenditure of cellular energy

Types of passive transport

simple diffusion, facilitated diffusion, osmosis

Passive transport concentration gradient

molecules/ions will spread/diffuse from where they are highly concentrated to where they are less concentrated until they are equally distributed in that space

Simple diffusion

mostly nonpolar solutes

Simple diffusion requirements

movement of molecules from high to low concentration, membrane is permeable (ex. lipids, O2, CO2, alcohol)

Facilitated diffusion

charged or polar substrates (ex. ions, glucose, amino acids)

Osmosis

movement of a solvent in or out of the cell's membrane towards higher solute

Osmosis through

protein channels (aquaporins) or slipping between the lipid tails of the membrane despite its polarity

Tonicity

measures the ability of a solution to change the volume of a cell by osmosis

Hypertonic

high concentration of solutes

Hypotonic

low concentration of solutes

ECF

extracellular fluid outside the cell

Active transport

movement of solutes using energy (like ATP) and forces molecules to move from low to high concentrations (AGAINST gradient)

Transport takes into consideration

type of solute, membrane's permeability, intra- and extracellular concentration of solute

Active transport uses

membrane proteins and/or vesicles

Primary active transport uses

ATP to directly move solutes through transmembrane proteins

Primary active transport can

work together with other active or passive transport systems to move multiple solutes across the membrane

Transmembrane proteins for active transport

symporters, anti porters, uniporters

Symporters

transport two solutes in the same direction

Antiporters

transport two solutes in opposite directions

Uniporters

transport one solute

Secondary active transport (coupled transport)

uses ATP to indirectly move solutes + requires original gradient created by primary active transport

Original energy from primary active transport

the energy used to move additional, or secondary molecules either with or against their concentration gradients

Active transport - vesicles

used to transport larger solutes (ie. polar macromolecules) within transport vesicles made by enclosing portion of the phospholipid bilayer around solute

Endocytosis

bringing INTO the cell - phagocytosis, pinocytosis, receptor mediates

Phagocytosis

cell "eating"

Pinocytsos

cell "drinking" aqueous solutions

Receptor mediated endocytosis

uses membrane proteins to target specific solutes

Exocytosis

solutes released out of the the cell

Animal and plant cells

secrete hormones, digestive enzymes, signaling molecules for communication

Plant cells

secrete cell wall solutes

Prokaryotic cells

cytoplasm surrounded by plasma membrane within a cell wall

Prokaryotic cells have an

absence of a membrane bound nucleus and have free-floating DNA organized as a nucleoid

Cell wall made of

peptidogylcan

Prokaryotic cell organelles

ribosomes, cytoskeleton (actin and tubulin)

Nucleus

contain all genetic information (DNA) within is the nucleolus that synthesizes ribosomal RNA

Nucleus structure

bound by a nuclear envelope made from a phospholipid bilayer

Endomembrane system

endoplasmic reticulum, golgi apparatus, vesicles

Endomembrane system functions

producing, packaging, and exporting certain cellular products

Endoplasmic reticulum structure

interconnected phospholipid bilayer flattened sacs. connections to nucleus and golgi apparatus

ER function

synthesis and modify proteins

rough ER

portion of outer membrane studded with ribosomes

Smooth ER

synthesis and modify lipid molecules, stores intracellular calcium

Smooth ER structure

without ribosomes

Intermediate filaments function

work with microtubules and link cells to other cells by forming special cell-to-cell junctions for tissues

Golgi and vesicles function

refines, sorts, packages and prepares for transport - proteins and lipids synthesized on the ER's membranes

Golgi and vesicles structure

flattened membranous sacs

Golgi and vesicles --\>

products enter golgi's membrane at the CIS FACE, products exit the golgi's TRANS FACE membrane within vesicles of golgi membrane

Lysosomes (specialized vesicles) function

digestive vesicle with enzymes that break down and digest unneeded cellular components, such as damaged organelles, or cellular foods

Cellular food

obtain nutrients for cell use that may be brought into the cell by an endosome (food vacuole)

Cytoskeleton functions - microtubules

maintain cell shape and structure, resist compression, position organelles within the cell

Cytoskeleton structure - microtubules

composed of protein subunits called tublin

Microfilaments structure

composed of protein subunits called actin

Microfilaments functions

(depends on placement); large component of muscle tissue - critical for muscle contraction, cell movement, vision of daughter cells during cell division

Intermediate filaments structure

made up of a variety of proteins such as keratin (protein in our hair)

Peroxisomes (specialized vesicle) function

perform lipid metabolism (breakdown fatty acids), synthesize phospholipids, perform chemical detoxification

Peroxisomes structure

formed by vesicles released from the ER that import peroxisomal proteins

Two or more cell types

working together creates tissue (utilize cell-to-cell junction - intermediate filaments)

Tight junctions

unique to vertebrates; acts as a wall within tissues to keep molecules from crossing over

Adhesive junctions

found in tissues with mechanical stress; attach cytoskeleton of a cell to cytoskeleton of other cells

Communicating junctions

permit small molecules or ions to pass from adjacent cells

Cytoplasm

surround the organelles

Cytoplasm contents

chloroplasts, vacuole, nucleus, centrioles, ribosomes, ER, golgi apparatus, vesicles (lysosomes, peroxisomes), mitochondria

Cytoskeleton

microfilaments, microtubules, intermediate filaments

Ribosomes function

facilitate protein synthesis

Ribosomes location

attached to the endoplasmic reticulum or FREE in cytoplasm

Ribosomes structure

ribosomal RNA (rRNA) and two protein subunits

Kingdom eukarya

extensive endomembrane system throughout interior

Plants usually lack

centrioles

Plants, fungi, and many protist

have cell walls surrounding the cell membrane made with cellulose or chitin

Centriole function

assembly and organization of microtubules for cell division

Centriole structure

pairs of barrel shaped organelles, contains a region with tubulin, a protein making up microtubules

animal cells do not

contain a vacuole or chloroplasts

Vacuole (specialized vesicle) functions

maintains osmotic balance, store molecules like sugars, ions, perform enzymatic digestion of macromolecules

Vacuole structure

membrane system with channels for water called tonoplasts

Chloroplasts function

synthesize food from sunlight using pigments called chlorophyll

Chloroplasts structure

surrounded by 2 membranes encasing a closed compartment of stacked membranes called grana (plural)

Homeostasis

maintain and balance internal environment that's different than external environment

osmotic pressure

cell's tendency to take in water by osmosis

Isotonic

no net water movement

Osmoregulation

balance of water and solutes

osmoconformers

live in marine environments - maintain body fluids with a solute concentration equal to that of the surroundings

ICF of osmoconformers

isotonic to saltwater --\> maintain osmostic equilibrium with external environment

Osmoregulators

(all other vertebrates) - internal solute concentrations are independent from the external environment

Freshwater vertebrates

have higher internal solute concentration than environment --\> need to remain hypertonic to freshwater