Lecture Exam 1 Chapter 3

List the general parts of a cell

Plasma (cell) membrane, cellular organelles, nucleus, cytoplasm

Four main functions of cells

Metabolism and energy use, synthesis of molecules, communication, reproduction/inheritance

4 main function of a cell acronym

MSCR- May (metabolism) She (synthesis of molecules) Come ( communication) Run( reproduction)

metabolism

sum of all chemical reactions that occur in the body

Energy released from metabolism is used for

synthesis of new molecules and muscle contraction

_________ produced from metabolism helps maintain normal body temp.

Heat

Relate and explain the functions of the cell in synthesizing molecules

Structural/functional characteristics are determined by the types of molecules produced; cells differ based on the types of molecules synthesized/ A cell’s identity and job come from the molecules it produces.

Relate and explain the functions of cell communication

Cells produce and respond to chemical and electrical signals that allow communication with other cells

Relate and explain the functions of reproduction/inheritance

Cells contain a complete copy of all the genetic information of an individual, which determines structural and functional characteristics, and during the growth process, cells divide to produce new cells that contain genetic information/

Cells contain all your genetic instructions, and they pass those instructions to new cells so your body can grow, repair, and function correctly.

plasma membrane

Outermost component of the cell. Selective barrier that regulates what moves in and out of the cell. Contributes to the communication between cells.

Describe the functions of the plasma membrane

Functions include supporting cell contents, regulating what moves in and out of the cell by selective barrier, communication between cells, and separation of intracellular and extracellular substances

acronym for plasma membrane function

SRS- Some( supporting) Real (regulating what enters and exits cells) S ( separating intracellular and extracellular substances)

Describe the general structure of the plasma membrane

45-50% lipids, 45-50% proteins, 4-8% carbohydrates

Lipid bilayer composed of ________________

phospholipids and cholesterol; proteins( channels, pumps, receptors) is embedded or extends out into the surface of the lipid bilayer

The plasma membrane is the _____________ of the cell.

entire outer boundary, The plasma membrane is the whole structure, and the lipid bilayer is the main part of it.
So the plasma membrane contains the lipid bilayer — it’s not only the lipid bilayer.

Lipid Bilayer

• Double layer of phospholipid molecules.

• Forms a barrier between   the inside and outside of the cell.

the head of the lipid bilayer is

polar and hydrophilic , faces intracellular and extracellular

the tails of the lipid bilay is

nonpolar and hydrophobic, fatty acid containing, and faces inside of plasma membrane

membrane potential

A membrane potential is the tiny electrical charge difference between the inside and outside of a cell. It’s like the cell has a small battery built into its membrane.

Why a membrane potential forms

• The membrane lets some ions pass and blocks others.

• This uneven movement creates different charges inside vs. outside the cell.

• That difference in charge = membrane potential.

Describe the functions of membrane lipids

Provide a lipid bilayer, which is a double layer of phospholipid molecules that form a barrier between the inside and outside of the cell

membrane lipid

Membrane lipids are the fat-based molecules that make up the main structure of the plasma membrane. They form the flexible, protective barrier around the cell.

What is the polar region

Hydrophillic region, phosphate-containing, faces intracellular and extracellular water (heads)

What is the nonpolar region

Hydrophobic (water-fearing) region, does not contain phosphate, faces inside of the plasma membrane (tails)

Explain the nature of the fluid-mosaic model of membrane structure

The plasma membrane is flexible and can change shape and composition through time - able to distribute molecules, allows for repair, and enables fusion of membranes

Describe the difference between integral and peripheral membrane proteins

Integral proteins penetrate deeply into the lipid bilayer, extending from one surface to another

Peripheral proteins attach to either the inner or outer surfaces of the lipid bilayer

Peripheral proteins

attach to either the inner or outer surfaces of the lipid bilayer

integral proteins

penetrate deeply into the lipid bilayer, extending from one surface to another

Name membrane proteins

Marker Molecules

Attachment Proteins

Transport Proteins

Channel Proteins

Carrier Proteins

ATP-Powered Pumps

Receptor Proteins

Enzymes

membrane protein acronym

MAT C CARE - Marker proteins Attachment proteins Transport proteins Channel proteins Carrier proteins ATP- powered pumps Receptor proteins Enzymes

Marker Molecules:

allow for intercellular recognition and communication - glycoproteins and glycolipids

Attachment Proteins:

integral proteins allow cells to attach to other cells or extracellular molecules

Transport Proteins:

integral proteins that allow ions or molecules to move across the plasma membrane

Channel Proteins:

non-gated ion channels are always open and are responsible for the permeability of the plasma membrane to ions, gated ion channels can be opened or closed by certain stimuli

Carrier Proteins:

integral proteins that move ions from one side of the membrane to the other

ATP-Powered Pumps:

transport proteins that use energy derived from the breakdown of ATP to move specific ions or molecules from one side of the plasma membrane to the other

Receptor Proteins

membrane proteins or glycoproteins that have an exposed receptor site on the outer cell surface

Enzymes

protein that acts as a catalyst

Movement of ions or molecules by carrier proteins can be classified in three ways:

Uniport

Symport

Antiport

Antiport

simultaneous movement of two different ions or molecules in the opposite direction across the plasma membrane

Symport

two different molecules or ions are moved across a biological membrane in the same direction

Uniport

movement of one specific ion or molecule across the plasma membrane

specificity

transport protein moves a single type of molecule or ion

Competition

similarly shaped molecules or ions compete for the transport protein

Saturation

rate of transport of molecules or ions limited to # of carrier proteins

phospholipid bilayer with embedded proteins allows ___________ to diffuse freely

small, nonpolar molecules like oxygen and carbon dioxide

do nonpolar molecules require energy to diffuse

nonpolar molecules do not require energy to diffuse across the membrane. They move by simple diffusion, which is passive.

What requires energy to move across phospholipid bilayer

• Polar molecules

• Ions

• Large molecules

These need channels, carriers, or pumps — and pumps require ATP.

How do polar molecules move across phospholipid bilayer

polar molecules, ions, and larger substances require the help of specific transport proteins to cross, and some transport may even require energy to move substances against their concentration gradients

plasma membrane

a selective (permeable) barrier that manages what goes into and out of the cell

List three ways that molecules and ions can pass through the plasma membrane

Diffusion

Osmosis

Facilitated diffusion

Facilitated diffusion

move large, water-soluble molecules or electrically charged molecules across the plasma membrane

Osmosis

a passive transport process where water moves across a semipermeable membrane toward higher solute concentration

Diffusion

random movement of molecules results in net movement from areas of higher to lower concentration

Discuss the process of diffusion and relate it to a concentration gradient

Diffusion is the tendency of ions and molecules to move from an area of higher concentration to an area of lower concentration in a solution

Explain the role of osmosis

Osmosis is the diffusion of water molecules across a selectively permeable membrane (plasma membrane)

Explain the role of osmotic pressure in controlling the movement of water across the plasma membrane

Osmotic pressure is the force required to prevent water from moving by osmosis across a selectively permeable membrane

Hypotonic

: lower concentration of solutes and higher concentration of water than inside the cell - water moves by osmosis into the cell, causing it to swell

Hypertonic:

higher concentration of solutes and lower concentration of water than inside the cell - water moves by osmosis from the cell into the solution, causing it to shrink

Isotonic:

concentration of solutes and water is the same inside and outside the cell - cells remain unchanged

Describe mediated transport

Process by which membrane proteins mediate or assist in the large movement of large, water-soluble molecules or electrically charged ions or molecules across the plasma membrane

Mediated transport, including the structure and function of the sodium/potassium pump

NA+/K+ pump creates electrical potentials across membranes, moves NA+ out of the cell, and moves K+ into the cell via the energy released from the breakdown of ATP to ADP

Endocytosis:

uptake of material into the cell (through the plasma membrane) by a vesicle

Exocytosis:

secretion of materials out of the cell through the formation of a vesicle

Subcategories of endocytosis

Phagocytosis, pinocytosis, receptor-mediated endocytosis

Subcategories of endocytosis acronym

PPR

Define phagocytosis

"Cell-eating" solid particles are ingested and phagogentic through particles formed

Define pinocytosis

"Cell-drinking" is the uptake of small droplets of liquids and the materials in them

Define receptor-mediated endocytosis

Plasma membrane receptors bind to specific molecules that are then taken into the cell

Describe the composition of the cytoplasm

Structure: material located between the nucleus and plasma membrane, 50 % cytosol and 50% organelles

functions of the cytoplasm

Functions: contains cytosol, the fluid portion of the cytoplasm that holds the organelles and the cytoskeleton, which supports the cell and enables it to change shape

Describe the structure of the nucleus and nucleoli

Largest organelle located in the center of cell, may be spherical, lobed, or elongated in shape,

difference between nucleus and nucleoli

The nucleus is the whole structure that holds the cell’s DNA.
The nucleolus is a small part inside the nucleus that makes ribosomes.

They are not the same thing — the nucleolus lives inside the nucleus.

Ribosomes

cell’s protein‑making machines/ They read genetic instructions and assemble amino acids into proteins.

function of the nucleus and nucleoli

houses DNA that contains genes that influence the structure of proteins and the structure and function of the cell

Describe the structure of the nucleoli

Spherical, well-defined body WITHIN the nucleus with no surrounding membrane

function of the nucleoli

produces rRNA and is the site of ribosomal subunit assembly

Integrins

 Attach cells to extracellular molecules.

Cadherins

Attach cells to other cells.

Nuclear envelope:

• Two separate membranes  surrounding nucleus  containing nuclear pores: Holes where materials can  pass between nucleus and  cytoplasm.

ribsomes are the site of

•  protein synthesis. May be found free within the cytoplasm or attached  to the endoplasmic  reticulum.

• Describe the functions of membrane lipids.

• Provide the membrane with added stability

• Limits the movement of phospholipids 

Explain the structure of ribosomes

composed of large and small subunits - free and attached ribosomes

function of ribosomes

site of protein synthesis within the cell

Explain free and attached ribosomes

Free: not attached to organelles, free within the cytoplasm

Attached: attached to the endoplasmic reticulum

functions of the rough endoplasmic reticulum

major site of protein synthesis

Rough ER: Studded with

•  ribosomes. Major site of protein synthesis. Occurs at the ribosome.

functions of Smooth ER

major site of lipid and carbohydrate synthesis

structure of rough ER

studded with ribosomes,

structure of Smooth ER

no attached ribosomes/ Major site of lipid and carbohydrate synthesis

Discuss the structure of the Golgi apparatus

Structure: flattened membrane sacs stacked on top of each other

function of the Golgi apparatus

Collect, package, and distribute proteins and lipids produced by the endoplasmic reticulum for secretion or internal use

Describe the role of secretory vesicles in the cell

Membrane-bound sacs that transport material from the Golgi apparatus to the exterior of the cell

lysosomes role

They digest ungested bacteria, viruses, and toxins, degrade nonfunctional organelles, break down glycogen, and release thyroid hormone, break down non-useful tissue and bone to release Ca2+

lysosomes and peroxisomes __________

digest material within the cell

structure of lysosomes

Lysosomes are membrane-bound vesicles formed by the Golgi apparatus.

structure of peroxisomes

Membranous sacs containing oxidases and catalases. Breakdown fatty acids, amino acids, and hydrogen peroxide. Detoxify harmful or toxic substances

roles of peroxisomes

They break down fatty acids, amino acids, and hydrogen peroxide, detoxify harmful or toxic substances, and neutralize free radicals

the structure of mitochondria

• Have a smooth outer  membrane and an inner

• membrane that is in folded to  produce cristae.

• Contain their own DNA

• Can produce some of their  own proteins.

• Can replicate independently of the cell

function of mitochondria

major site of ATP synthesis