Ap Bio Chapter 5 with review

What is the function of the proteins in the cell membrane

1. Support 2. Transport through the membranes 3. Communication & cell identification

What are the 3 types of transmembrane proteins

1. carriers - actively or passively transport molecules across membranes 2. Channel proteins - passively transport molecules across membrane 3. Receptor proteins - transmit information into the cell

Cellular membrane contain four components

1. phospholipid bilayer 2. transmembrane proteins 3. Internal protein network providing structural support 4. cell-surface markers (glycoproteins and glycolipids)

Describe phagocytosis

A cell engulfs a particle by wrapping pseudopodia around it and packaging it within a vacuole.

Describe the fluid-mosaic model of membrane structure by Singer and Nicolson

A mosaic of proteins float in or on a fluid lipid bilayer

Which of the following best describes the general structure of a cell membrane? A.) proteins embedded in two layers of phospholipid B.) a layer of protein coating a layer of phospholipid C.) phospholipids sandwiched between two layers of protein D.) proteins sandwiched between two layers of phospholipid

A. proteins embedded in two layers of phospholipid

Most cellular work is accomplished by _____ energizing molecules by _____ them.

ATP ... phosphorylating

Differences between active transport and facilitated diffusion?

Active transport requires the expenditure of cellular energy, and facilitated diffusion does not. Which of the following is a difference between active transport and facilitated diffusion?

Describe active transport. What type of transport proteins are involved, and what is the role of ATP in the process

Active transport uses energy to move materials against a concentration gradient with the use of a carrier protein or pump ATP provides the energy to power the conformation changes

What is active transport?

Active transport works with the assistance of proteins to move molecules from areas of low concentration to areas of high concentration. Think of a fish swimming up stream

Peter Agre received the Nobel Prize in 2003 for the discovery of aquaporins. What are they?

Aquaporins are specialized channels for water

nucleolus

Assembly of ribosomes take place here

Green olives may be preserved in brine, which is a 20-30% salt solution. How does this method prevent contamination by microorganisms?

Bacteria can't survive in a hypertonic solution because they lose water.

What is the difference between phagocytosis and pinocytosis

Both are forms of endocytosis (uptake of bulk material by the formation of a vesicle through the plasma membrane). Phagocytosis is "cell eating" (solid object) and pinocytosis is "cell drinking" (extracellular fluid).

Mitocondria

Break down glucose into ATP (energy for the cell) This is where anaerobic respiration occurs

Peroxisome

Breaks down fatty acids In animal cells, the long fatty acids are converted to medium chain fatty acids, which are subsequently shuttled to mitochondria where they are eventually broken down to carbon dioxide and water.

Microvilli

Cells may have slender extensions of the cell membrane to form cilia or the smaller extensions called microvilli. The microscopic microvilli effectively increase the surface area of the cell and are useful for absorption and secretion functions

Chloroplast

Chloroplasts work to convert light energy of the Sun into sugars that can be used by cells.

Proteins perform a number of functions within membranes. Which of the following statements is true about membrane proteins? A.) Proteins keep the membrane fluid. B.) Proteins form the basis of the semipermeable membrane. C.) Proteins facilitate membrane stabilization. D.) Proteins can bind other molecules, which may trigger specific cellular functions.

D. Proteins can bind other molecules, which may trigger specific cellular functions.

Which of these statements describes what occurs in facilitated diffusion? A.) Facilitated diffusion requires energy from the cell to drive a concentration gradient. B.) Facilitated diffusion of solutes occurs through phospholipid pores in the membrane. C.) Facilitated diffusion is another name for osmosis. D.) Facilitated diffusion of solutes occurs through protein pores in the membrane

D.) Facilitated diffusion of solutes occurs through protein pores in the membrane

Describe 3 types of Passive Transport

Diffusion Osmosis Facilitated Diffusion

Nucleoid

Hereditary material that controls cell growth, matience, and reproduction Only in procaryotic cells, b/c in eukaryotic cells the nucleus is surrounded by a cell membrane whereas the nucleoid is not where DNA Is present

Why doesn't the antibiotic penicillin harm humans?

Human cells do not have cell walls.

Tight-Junctions

Limits the passage of molecules and ions through the space between the cells prevents leakage

Integral Membrane Protein

Make sure you know which region is the hydrophilic region, hydrophobic region. Here you can see the alpha-helical configuration. In these two proteins, the left side is a single pass protein and the right side protein is a multi-pass protein. Integral proteins are mainly found either fully or partially submerged in the phospholipids bilayer of the plasma membrane. These proteins have both polar and non-polar regions on them. Polar heads protrude from the surface of the bilayer while non-polar regions are embedded in it. Usually only the non-polar regions interact with the hydrophobic core of the plasma membrane by making hydrophobic bonds with the fatty acid tails of the phospholipids. The integral proteins that span the entire membrane from the inner surface to the outer surface are called transmembrane proteins. In transmembrane proteins, both ends that project out of the lipid layer are polar or hydrophilic regions. The middle regions are non-polar and have hydrophobic amino acids on their surface

in which categories does the tight-junctions appear?

ONLY IN ANIMAL CELLS!!

What are two general types of transport? Talk about whether it uses ATP or not and talk about the concentration.

Passive Transport: No ATP High Concentration --> Low Concentration Active Transport: Uses ATP Low Concentration --> High Concentration

passive transport

Passive transport requires no expenditure of cellular energy.

Passive Transport

Passive transport transports molecules without the assistance of proteins from an area of high concentration to an area of lower concentration.

Peripheral membrane protein

Peripheral proteins (extrinsic proteins) are present on the innermost and outermost of phospholipids bilayer. These proteins are loosely bound to the plasma membrane either directly by interactions with polar heads of phospholipids bilayer or indirectly by interactions with integral proteins. Most of the peripheral proteins are found on the innermost surface or cytoplasmic surface of the membrane

What represents osmoregulation in organisms?

Plant cells need a hypotonic environment in order to stay turgid

5 Forms of Active Transport

Proton Pump Sodium Potassium Pump Phagocytosis Pinocytosis Receptor mediated endocytosis

Which of these statements about enzyme inhibitors is true?

The action of competitive inhibitors may be reversible or irreversible.

Cell Membrane

The cell membrane controls what goes in and out of the cell

The membrane is referred to as a "fluid mosaic" structure. Which of the following statements is true?

The fluid is phospholipid, and the mosaic is protein.

Chromatin

The function of chromatin is to efficiently package DNA into a small volume to fit into the nucleus of a cell and protect the DNA structure and sequence. Packaging DNA into chromatin allows for mitosis and meiosis, prevents chromosome breakage and controls gene expression and DNA replication.

Cytoplasm

The liquid that fills the cell so the material or protoplasm within a living cell All organelles of prokaryotes are in the cytoplasm because they do not have cell walls to separate them Receives this shape from the Cytoskeleton

What is meant by membrane fluidity? Describe the movements seen in the fluid membrane?

The phospholipids are free to move along the plane of the lipid bilayer. Unanchored proteins may also move slowly .

What is the water potential equation?

Water potential = Water potential P + Water potential S

What is the equation in finding out Water solute potential?

Water solute potential = iRCT

Plasmodesmata

a channel through a cell wall that allows for substances to move from cell to cell

Define concentration gradient

a difference in concentration of a substance from one location to another, often across a membrane

The concentration of solutes in a red blood cell is about 2%. Sucrose cannot pass through the membrane, but water and urea can. Osmosis would cause red blood cells to shrink the most when immersed in which of the following solutions?

a hypertonic sucrose solution

Centrosome

a place where those microtubules become organized into centrioles (the things that pull them apart)

isotonic

a solution having the same concentration of solute

hypertonic

a solution with a higher concentration of solute

hypotonic

a solution with a lower concentration of solute

When in solution, a molecule that moves slowly across an artificial membrane moves rapidly across a plasma membrane. This occurs regardless of whether the concentration of this molecule is higher inside or outside the cell. Using this information, which transport mechanism is most likely to be responsible for the movement of the molecule across a plasma membrane?

active transport

Cellular respiration is an example of _____.

an exergonic reaction

Lysosome

breaks down larger food molecules into smaller molecules Lysosomes are organelles that contain digestive enzymes. They digest excess or worn out organelles, food particles, and engulfed viruses or bacteria.

receptor-mediated endocytosis

bulk transport of substances into the cell where the molecules must first bind to specific receptors in the plasma membrane

Distinguish between channel proteins and carrier proteins

channel - passively transports molecules across membrane by creating a selective tunnel carrier proteins - actively or passively transports molecules through conformational changes

Stability of an animal cell plasma membrane is enhanced by _____.

cholesterol molecules

How do the follow cross the membrane: - CO2 - Glucose - O2 - H2O

co2 - simple diffusion (passive ) from high concentration to low concentration regions glucose - active transport of ions to form a gradient. glucose transport is coupled with the ions movement down the concentration gradient (i.e. Na+ moves back from outside the cell where there is a high concentration of Na+ and takes with it glucose). An example of symport transport O2 - simple diffusion (passive) from high concentration to low cconcentration regions Osmosis (passive) of water from areas of low solute concentration to high solute concentration or high water potential to low water potential or from pure water to less pure water

What is countertransport?

coupled transport where the inward movement of a substance drives the outward movement of another substance

Ribosome

creation of proteins

The movement of atoms, ions, or molecules from a region of higher concentration to regions of lower concentration is called _____.

diffusion

exocytosis

discharge of material from vesicles

The phosphorylation of ADP to form ATP is an _____ reaction that _____ energy.

endergonic ... requires an input of

A nursing infant is able to obtain disease-fighting antibodies, which are large protein molecules, from its mother's milk. These molecules probably enter the cells lining the baby's digestive tract via _____.

endocytosis

pinocytosis

endocytosis of a liquid

phagocytosis

endocytosis of a particulate

If the entropy of a system is increasing, this means that _____.

energy input will be needed to maintain organization

What is facilitated diffusion? Is it active or passive? Cite two examples.

facilitated = diffusion mediated by membrane proteins; passive transport Two examples: - movement of ions through a protein channel - movement of amino acids through a carrier protein

What condition might result from an excess of aquaporins?

fluid retention in pregnant women

Phospholipids are well suited to be the main structural components of membranes because they _____.

form a selectively permeable structure

When considering the formation of membranes, they _____.

form spontaneously in aqueous environments

Distinguish between glycolipids and glycoproteins

glycoproteins - proteins/carbohydrate chain characteristic of an individual (ie MHC - helps recognize the individual) glycolipids - lipid/carbohydrate chain shape characteristic of tissue

Membrane carbohydrates are important in cell-cell recognition. What are two examples of this?

glycoproteins = major histocompatibility complex glycolipid = A B O blood group marker

Centriole

helps in cell division (the spindles that pull apart the DNA)

water moves from areas of _____________ water potential to areas of ____________ water potential

high; low

If the volume of a cell increases when it is placed in an aqueous solution, that solution is said to be _____ to the cell

hypotonic

endocytosis

infolding of the plasma membrane allowing for bulk transport of substances into a cell

Membrane proteins are the mosaic part of the model. Describe each of the two main categories: - integral proteins - peripheral proteins

integral proteins - proteins embedded in the membrane that protrude through to the interior and exterior peripheral proteins - proteins associated with the surface of the membrane. Some act as identification proteins (MHC), others act as receptor proteins.

Nuclear Membrane

is the membrane that encloses the nucleus. This bilayer membrane is made of lipids, and encases the genetic material in eukaryotic cells. The nuclear membrane is made up of a double lipid bilayer.

What happens when water moves into a cell? and when it moves out?

it gets bigger, and when it moves out it shrinks

If the tertiary structure of an enzyme is changed, _____.

its substrate may not fit properly in the active site

The mechanism of enzyme action is to _____.

lower the energy of the activation of a reaction

Large Vacuole

maintain the proper pressure with the plant cells to provide structure and support for the growing plant Stores food, water, waste

Cell wall

maintains shape and it is a protective barrier

What is membrane potential? Which side of membrane is positive?

membrane potential = voltage difference; an electrical potential difference across a membrane; from the Na/K pump, the outside of the cell membrane is more +

Cytoskeleton

microtubules the cell to maintain its shape and 3D structure as well as help organize the cell's parts. In addition, it provides a basis for movement and cell division Think Train tracks!

The diffusion of water across a selectively permeable membrane is called _____.

osmosis

Is diffusion a passive or active process?

passive

Some liver cells ingest bacteria, a function probably accomplished by _____.

phagocytosis

Which of the following terms specifically refers to the intake of very large particles by cells?

phagocytosis

turgid

pressurized state of a plant cell resulting from osmotic intake of water pressing the cell wall against the cell membrane and the membrane against the wall

What is the purpose of the phospholid bilayer in membranes

provides permeability barrier and allows proteins to stay in place; excludes water-soluble molecules from nonpolar interior of bilayer and cell

What enables a cell to pick up and concentrate a specific kind of molecule?

receptor-mediated endocytosis

Seawater is dangerous to drink because _____.

seawater is hypertonic to your body tissues and drinking it will cause you to lose water by osmosis

Water potential is the combined effects of ______________ concentration and ___________ ______________; this determines water movement.

solute concentration; physical pressure

Golgi Body

sorts and packs protein into vesicles and transports them The job of the Golgi apparatus is to process and bundle macromolecules like proteins and lipids as they are synthesized within the cell.

flaccid

state of a plant cell placed in an isotonic solution

The first law of thermodynamics _____.

states that energy is neither created nor destroyed

Nucleus

the central and most important part of an object, movement, or group, forming the basis for its activity and growth.

What are the two forces that drive the diffusion of ions across the membrane? What is the combination of these forces called

the chemical force (concentration gradient) and the electrical force (repulsion & attraction)

osmosis

the diffusion of water across a selectively permeable membrane which goes from the side containing the lower concentration of solute to the side containing higher concentration in absence of differences in pressure or volume

Endoplasmic Reticulum

the folding of protein molecules in sacs called cisternae and the transport of synthesized proteins in vesicles to the Golgi apparatus.

passive transport

the movement of substances across a cells' membrane WITHOUT the expenditure of energy

Define diffusion

the net movement of dissolved molecules or other particles from a region where they are more concentrated to a region where they are less concentrated

A reaction is designated as exergonic rather than endergonic when _____.

the potential energy of the products is less than the potential energy of the reactants

plasmolysis

the shrinking of a plant cell in a hypertonic solution such that it pulls away from the cell wall

Describe major functions of membrane proteins - Transport - Enzymatic Activity - Cell Surface Receptor (signal transduction) - Cell-surface (cell-cell) recognition cell-to-cell adhesion (intercellular joining) - attachment to cytoskeleton and ECM

transport - transmembrane proteins that move specific molecules through the membrane in a series of conformational changes or providing a tunnel (ie carrier proteins, Na/K pump, etc.) - Enzymatic activity: carry out many chemical reactions on the interior surface of the plasma membrane Cell Surface Receptor (signal transduction) - transmembrane proteins that bind signal molecules which in turn induces activity within the cell Cell-surface recognition- glycoproteins such as the MHC is used for cell recognition by creating a protein/carbon chain characteristic of an individual Cell to cell adhesion - proteins that "glue" cell together by forming temporary interactions and more permanent bonds attachment to cytoskeleton and ecm: surface proteins that interact with other cells and are often anchored to the cytoskeleton by linking proteins

Are transport proteins specific? Cite an example that supports your response

yes - transport proteins are specific Na/K pump only move Na out of the cell and K into the cell