1. All living organism are made of cells 2. Cells cannot be broken down bc they are the smallest units of life 3. New cells can only come from pre-existing cells by cell division

Chapters 4&5 Flashcards by Aubrie Edington

Compare and contrast the general features of prokaryotic and eukaryotic cells

Prokaryotic cells lack a membrane-enclosed nucleus and have a simple structure
Eukaryotic cells have a nucleus (YOU have a brain/nucleus) and have an intense organized structure

How well did you know this?

Not at all

Perfectly

Describe the 3 types of protein filaments that make up the cytoskelaton

microtubules, intermediate, actin

How well did you know this?

Not at all

Perfectly

Rough vs. Smooth endoplasmic reticulum

rough: studded with ribosomes on the outer surface making it look “bumpy” or rough; assists in sorting proteins
Smooth: lacks ribosomes and functions in divers metabolic processes

How well did you know this?

Not at all

Perfectly

Identify the structures and functions of mitochondria and chloroplasts

Both of these organelles are considered semiautonomous bc they grow and divide but depend on other parts of the cells for their internal components.
Mitochondria: supplies most of the cells ATP; has outer membrane, intermembrane space, inner membrane encloses the mitochondrial matrix which encloses the cristae
Chloroplasts: captures light energy and uses some to synthesize organic molecules like glucose [photosynthesis]; has outer membrane, inner membrane, thylakoid membrane, thylakoid lumen, and the stroma (enclosed by inner membrane but outside thylakoid membrane)

How well did you know this?

Not at all

Perfectly

Endosymbiosis theory

mitochondria and chloroplasts originated from an endosymbiotic relationship that gave rise to eukaryotic cells

How well did you know this?

Not at all

Perfectly

Co-translational vs post-translational

cotranslational sorting: first step in the sorting process begins while translation is occurring
post-translational sorting: occurs after the translation is finished

How well did you know this?

Not at all

Perfectly

List three important functions of the plasma membrane

Membrane transport: movement of ions or molecules across a biological membrane
Cell Signaling: cells sense change in their environment and communicate with each other
Cell adhesion: allows cells to bind to each other

How well did you know this?

Not at all

Perfectly

Discuss the fluid-mosaic model of the membrane structure

dynamic (change in appearance
The accepted model of a biological membrane
its basic framework is the semifluid phospholipid bilayer with a mosaic of proteins
Carbohydrates may be attached to the lipids or proteins

How well did you know this?

Not at all

Perfectly

Predict how changes in lipid composition affect membrane fluidity

The biochemical properties of phospholipids affect the fluidity of the phospholipid bilayer
Longer the tail, less fluid
unsaturated, more fluid

How well did you know this?

Not at all

Perfectly

Compare and contrast simple diffusion, facilitated diffusion, passive transport and active transport

Simple: moves across gradient (high to low) by passing DIRECTLY through the bilayer
Facilitated: a transport protein provides a passageway for a substance to cross a membrane from high to low gradient
Active: moves AGAINST the concentration gradient, which requires ATP

How well did you know this?

Not at all

Perfectly

Describe the process of osmosis and how it affects cell structure

Osmosis: movement of water across a membrane to balance solute
Hypotonic: swells the cells b/c water comes rushin in
hypertonic: running so fast = skinny legend/ cells shrink b/c water exits the cell

How well did you know this?

Not at all

Perfectly

Identify three different types of membrane proteins

transmembrane proteins: have one or more regions physically embedded in the hydrophobic interior of the phospholipid bilayer
Lipid-Anchored proteins: has a lipid molecule covalently attached to an amino acid side chain within the protein
Peripheral membrane proteins: associates with membranes in a third way = do not interact with the hydrophobic interior but rather are noncovalently bound to regions of integral membrane proteins that project out from the membrane; typically attached to the membrane by hydrogen and/or ionic bonds

How well did you know this?

Not at all

Perfectly

Explain the difference between primary and secondary active transport

Primary: involves the functioning of a pump [transporter that directly uses energy to transport a solute against the concentration gradient]
Secondary: process in which a pre-existing gradient drives the active transport of another solute

How well did you know this?

Not at all

Perfectly

Cell Theory

All living organism are made of cells
Cells cannot be broken down bc they are the smallest units of life
New cells can only come from pre-existing cells by cell division

How well did you know this?

Not at all

Perfectly

Amphipathic

have both polar and nonpolar regions

How well did you know this?

Not at all

Perfectly

Bilayer

lipid bilayer is a biological membrane consisting of two layers of lipid molecules [phospholipids]

How well did you know this?

Not at all

Perfectly

Liposomes

a vesicle surrounded by a phospholipid bilayer

How well did you know this?

Not at all

Perfectly

Cholesterol

Affects fluidity; stabilizes membranes; higher temps, less fluid
lower temps, more fluid

How well did you know this?

Not at all

Perfectly

Transporters

A transmembrane protein that binds a solute and undergoes a conformational change to allow the movement of the solute across a membrane aka carrier

How well did you know this?

Not at all

Perfectly

Enzymes

A protein that accelerates the rate of a chemical reaction

How well did you know this?

Not at all

Perfectly

Integral Membrane proteins

Lipid-Anchored proteins: has a lipid molecule covalently attached to an amino acid side chain within the protein

How well did you know this?

Not at all

Perfectly

Peripheral membrane proteins

Peripheral membrane proteins: associates with membranes in a third way = do not interact with the hydrophobic interior but rather are noncovalently bound to regions of integral membrane proteins that project out from the membrane; typically attached to the membrane by hydrogen and/or ionic bonds

How well did you know this?

Not at all

Perfectly

Transmembrane proteins

transmembrane proteins: have one or more regions physically embedded in the hydrophobic interior of the phospholipid bilayer

How well did you know this?

Not at all

Perfectly

Fluid mosaic model

How well did you know this?

Not at all

Perfectly

Plasma membrane

part of the endomembrane system

Cell wall

A relatively rigid, porous structure located outside the plasma membrane of prokaryotic cells and cells in plants, fungi, and certain protists; provides support and protection

Selectively permeable

allows only certain substances in and out

Diffusion

moving down/across the gradient without ATP

Channel

very selective and span the membrane, making hydrophilic tunnels across (allowing the target molecules to pass through by diffusion)

Carrier

membrane proteins that complement the structural features of the molecules transported

Osmosis

the movement of water across a membrane to balance solute concentrations

Active Transport

moves against the gradient with the help of ATP

Primary Active Transport

Needs a pump to be able to go up the gradient rather than using a pre-existing method of ATP

Electrochemical gradient

dual gradient across a membrane, having both electrical and chemical components; determines the direction in which ions will move

Secondary active transport

pre-existing gradient drives the active transport of another solute

Vacuole

a space between within the cell that's empty of cytoplasm, lined with a membrane, and filled with fluid (functions to hold various solutions or materials)

Nucleus

Eukaryotic cells have this; command center that regulates the activities of the cell

Prokaryotic

A cell lacking a nucleus and cell compartmentalization; Bacteria and Archaea

Eukaryote

[member of the domain: eukarya] has nucleus and extensive compartmentalization; fungi, plants, and animals

Nucleoid

A site in a bacterial cell where the genetic material (DNA) is located

Organelle

A subcellular structure or membrane-bound compartment with its own unique structure and function

Chloroplasts

site of photosynthesis

Cytoplasm

region of the cell that's contained within the plasma membrane

Mitochondria

produces energy = sugars that can be broken down for energy regulates the metabolic activity of the cell

Plasma membrane

The biological membrane that separates the internal contents of a cell from its external environment

Cytoskeleton three types of protein filaments

in eukaryotes a network within the cytosol consisting of 3 different types of protein filaments: microtubules, intermediate, and actin

Endoplasmic reticulum

A convoluted network of membranes in a cell’s cytoplasm that forms flattened, fluid-filled tubules, or cisternae

Lysosomes

A small organelle found in animal cells that contains acid hydrolases that degrade molecules and macromolecules

Golgi apparatus

A stack of flattened, membrane-bound compartments that performs three overlapping functions: secretion, processing, and protein sorting

Peroxisomes

A relatively small organelle that is found in all eukaryotic cells and that catalyzes detoxifying reactions

Cytosol

central coordinating region for metabolic activities

Plasmodesmata

canals that pass through plant cell walls and allows direct communication of molecules between adjacent plant cells

Vacuoles

organelle in cells that functions to hold various solutions or materials

Vesicles

help move materials

Endomembrane system and why it's important

group of membranes and organelles in eukaryotic cells that work together to modify, package, and transport lipids and proteins it allows different elements of the eukaryotic cell to be compartmentalized

Exocytosis vs Endocytosis

Nuclear envelope

encloses the nucleus

Nuclear pores

a passageway for the movement of molecules and macromolecules into and out of the nucleus; formed where the inner and outer nuclear membranes make contact with each other

Ribosomes

a structure composed of proteins and rRNA that's the site where translation of mRNAs and synthesis of polypeptides occurs

Lumen

internal space or hollow cavity of an organelle or an organ (endoplasmic reticulum, the stomach, or a blood vessel)

Rough vs. smooth endoplasmic reticulum

rough has ribosomes and plays a key role in the initial synthesis and sorting of proteins that are destined for other areas/outside of the cell Smooth doesn't have ribosomes and functions in diverse metabolic processes

Golgi Apparatus

directs, processes, sorts, and secretes cellular molecules

Lysosomes

subcellular organelles found in nearly all types of eukaryotic cells and are responsible for the digestion of macromolecules, old cell parts, and microorganisms

Protein sorting

Signal Sequences

a sorting signal in a polypeptide that is recognized by SRP, which allows the polypeptide to be directed to the ER membrane

SRP - Signal-recognition part

recognizes signal sequences and allows them to pass to the ER membrane

Like cell membranes, many fats and oils are made up in part of fatty acids. Most animal fats (like butter) are solid at room temperature, whereas plant fats (like canola oil) tend to be liquid. Can you predict which types of fat contain saturated fatty acids, and which type contain unsaturated fatty acids?

solid at room temp is saturated liquid at room temp is unsaturated

What are two ways proteins associate with membranes?

transmembrane proteins lipid-anchored protein Peripheral membrane proteins

What is the difference between passive and active transport?

active need energy = going against the gradient

What are the names and functions of the major organelles of the endomembrane system of eukaryotic cells?

Golgi apparatus, lysosomes, endoplasmic reticulum, vacuoles, nuclear envelope, peroxisomes, and plasma membrane

How does a protein end up free in the cytosol, embedded in the plasma membrane, or secreted from the cell?

signal-reception particle

Are mitochondria present in animal cells, plant cells or both?

both

Describe the factors that affect the fluidity of membranes

length of fatty acid tails, cholesterol and the temperature, and how saturated they are

What property of phospholipids makes them ideally suited to form membranes?

amphipathic (polar and nonpolar)

Briefly describe endosymbiosis

both molecules/cells in a relationship that benefits them both

Mitochondria and chloroplast have their own DNA and replicate separately from the nucleus and can synthesize ATP. Can they survive outside the cell? Explain your answer.

no because they still depend on other functions of the cell

What is the relationship between the components of the endomembrane system?

they are all related in some way and serve a purpose

Caffeine is a nonpolar molecule. What is the most likely method by which it is absorbed into cells? a. Facilitated diffusion b. Osmosis c. Active transport d. Diffusion e. Exocytosis

All are true except? a. Shorter fatty acyl tails make the membrane more fluid b. Saturated fatty acyl tails make the membrane more fluid c. Unsaturated fatty acyl tails make the membrane more fluid d. Cholesterol makes the membrane less fluid at higher temperatures e. Cholesterol makes the membrane more fluid at lower temperatures

What type of amino acids would you expect to find in the transmembrane portion of a membrane protein? a. Charged amino acids b. Polar amino acids c. Non-polar amino acids d. Hydrophilic amino acids

c because hydrophobic amino acids are found in this area. hydrophobic amino acids are nonpolar

Permeability refers to – a. the movement of molecules from an area of greater concentration to an area of lower concentration b. the amount of solute in a solution c. the extent a membrane allows a substance to pass through d. the state of being permanent e. the ability to establish a permanent solute level in a solution

The movement of water from an area of high concentration to an area of low concentration through a membrane is – a. Osmosis b. Active transport c. Solubility d. Insolubility e. Diffusion

Which of the following organelle is not part of the endomembrane system? a. Smooth endoplasmic reticulum b. Rough endoplasmic reticulum c. Golgi apparatus d. Nucleolus e. All are part of the endomembrane system

Blocking ribosomes prevents? a. Protein packaging b. Protein folding c. Protein secretion d. Protein assembly e. Protein absorption

Protein insertion into the ER membrane is typically — a. Cotranslational b. Pretranslational c. Posttranslational d. Quasitranslational

Sending proteins into mitochondria or chloroplasts is — a. Cotranslational b. Pretranslational c. Posttranslational d. Quasitranslational