Biology HW 3 Connect
Which of the following are functions of lysosomes?
-Breaking down macromolecules in the cell -Digestion of substances taken in by endocytosis -Recycling of building blocks to make new molecules
Identify the four main components of all eukaryotic membranes.
-Cell surface markers -Interior protein network -Transmembrane proteins -Lipid bilayer
Choose all functions typically carried out by membrane proteins.
-Connect adjacent cells and hold them together -Attach the membrane to the cytoskeleton -Receive external chemical messages
The functions of the rough endoplasmic reticulum include which of the following?
-Glycoprotein synthesis -Protein sorting -Protein synthesis
Which of the following describes the sodium-potassium pump?
-It is an active transport mechanism. -It moves sodium ions and potassium ions across the membrane in opposite directions.
Which of the following is one of the four main components of all plasma membranes?
-Lipid bilayer -Transmembrane proteins -Interior protein network -Cell surface markers
Identify the fibers which are used in the cell division of animal cells.
-Microtubules -Actin
Which of the following are the main types of cytoskeletal fibers?
-Microtubules -Intermediate filaments -Actin filaments
What happens in a peroxisome?
-O2 is used to help break down lipids. -Highly reactive molecules such as hydrogen peroxide are generated.
Select the accurate statements concerning membrane fluidity.
-Phospholipids are relatively free to move laterally within the membrane. -Unanchored proteins are relatively free to move laterally within the membrane.
Which of the following are the three main types of endocytosis?
-Pinocytosis -Receptor-mediated endocytosis -Phagocytosis
Water is attracted to which kinds of solutes, forming hydration shells around them?
-Polar -Charged
Which of the following are similarities between mitochondria and chloroplasts?
-Presence of DNA -Presence of protein synthesizing ribosomes.
Which of the following are similarities between mitochondria and chloroplasts?
-Presence of protein synthesizing ribosomes -Presence of DNA
Which of the following are typical components of biological membranes?
-Proteins -Lipids
How does lipid composition affect membrane fluidity?
-Sphingolipids tend to make the membrane less fluid. -Saturated fatty acids tend to make the membrane less fluid because they pack together well.
Choose the three groups of lipids found in eukaryotic cells.
-Sterols -Sphingolipids -Glycerol phospholipids
Functions of the smooth endoplasmic reticulum include which of the following?
-Storage of calcium -Assembly of membrane lipids -Steroid synthesis
The two solutions shown in this diagram are separated by a selectively permeable membrane that allows water to pass through freely but prevents the passage of urea. Before equilibrium is reached, which of the following statements are true?
-The solution on the left is hypertonic. -The water level will rise on the left side of the U-tube -Net movement of water across the membrane is toward the left.
Select all true statements about cadherins.
-They are divided into two types: I and II. -They are Ca2+-dependent proteins. -They have an extracellular domain that can interact with other cadherins.
Select the statements that are true about ions and how they interact with membranes and their components.
-They are repelled by the hydrophobic interior of the lipid bilayer. -They interact well with polar molecules.
Which of the following statements about ion channels are true?
-They are used to transport ions across the membrane. -Some can be opened or closed in response to a specific stimulus.
When phospholipids are placed in water, they spontaneously form which of the following?
A bilayer
Which of the following is found in eukaryotic cells, but not in prokaryotic cells?
A nucleus
endocytosis
A process in which a cell engulfs extracellular material through an inward folding of its plasma membrane.
Identify the two main domains that contain prokaryotes?
Bacteria and Archaea
Which method of microscopy, commonly used to study lipid bilayers, was used to produce this image?
Freeze-fracture microscopy
The cell wall of which type of cell is composed of chitin?
Fungal
Bulk Transport: Exocytosis
Moves materials out of the cell in membranous vesicle, which migrates to and combines with plasma membrane, then emptied to outside
How do carrier proteins differ from channel proteins?
Only carrier proteins actually bind to the substance being transported.
In a parasitic relationship, one organism benefits but harms the second organism.
Parasites do not always live inside the other species.
Which of the following is a eukaryotic organelle in which O2 is used to help break down lipids?
Peroxisome
Some cells contain a nucleoid but not a
nucleus
Hydrophobic lipids are made soluble in the cytoplasm by being coated with ___________. The result is a lipid droplet.
phospholipids
The lipid bilayer that forms the core of all cell membranes is composed primarily of
phospholipids
The largest vacuoles, which can occupy most of the cell volume, are found in which type of cell?
plant
pinocytosis
process by which a cell takes in liquid from the surrounding environment
What are the two types of life forms?
prokaryotes and eukaryotes
Not all cells require a nucleus, for example, consider
prokaryotic cells, such as bacteria and archaea.
Ribosomes are responsible for ___________ synthesis in the cell.
protein / polypeptide
Which of the following are key functions carried out by membrane proteins?
-Transport specific ions and molecules across the membrane -Catalyze specific chemical reactions on the surface of the membrane -Receive external chemical messages -Function as cell-surface identity markers
The core of lipid droplets could contain which of the following lipids?
-Triglycerides -Sterols
Compared to the ER membrane, the plasma membrane contains more
-phosphatidylcholine -cholesterol -sphingomyelin
Transport that requires a cell to expend some of its own energy, typically from ___________, is called _______________ transport.
ATP ; Active
The digestive enzymes in the lysosomes are optimally active at which of the following pH ranges?
Acidic
During the contraction of muscle cells, which fiber is used?
Actin
Which of the following organisms would be able to manufacture its own food?
Any organism that has chloroplasts
Which of the following might explain (at least to some extent) the greater thermal stability of archaeal membranes?
Archaeal membranes contain saturated hydrocarbons in a monolayer.
Which of the following best describes the relationship between solute concentration and rate of diffusion during facilitated diffusion by carrier proteins?
As solute concentration increases, the rate of diffusion increases but eventually it remains constant once it reaches a maximum rate.
Why do ions need membrane transport proteins to help them cross the plasma membrane?
Because they are charged
Which type of transport proteins use energy from ATP indirectly?
Coupled transport proteins
Desmosomes
Cadherins bind to intermediate filaments
adherens junctions
Cadherins bind to microfilaments
Which type of movement is made possible by the arrangement of actin fibers?
Cellular crawling
Which structure is involved in eukaryotic cell division?
Centrosome
The flattened stacks of membrane typical of the Golgi apparatus are called which of the following?
Cisternae
Plasmodesmata
Cytoplasmic connections between the cell walls of plants
The eukaryotic cell structure involved in supporting the shape of the cell and anchoring organelles to fixed locations is the
Cytoskeleton
Which part of the cell's primary function is to support cell shape and anchor organelles to fixed locations?
Cytoskeleton
Net movement of a substance from a region where it has a higher concentration to a region where it has a lower concentration is called which of the following?
Diffusion
What type of microscope can be used to see the two phospholipid layers in a plasma membrane, as in this image?
Electron
What term describes a relationship, in which a smaller cell lives inside a larger cell?
Endosymbiosis
Which of the following is NOT one of the four main components of all plasma membranes?
Extracellular matrix
Which structure forms a protective layer rich in glycoproteins on the surface of animal cells?
Extracellular matrix
Diffusion that is assisted by a channel protein or a carrier protein is called ____________ diffusion.
Facilitated
When a channel protein or carrier protein assists in diffusion, which of the following is observed?
Facilitated diffusion
Gap junctions
Involves connexon proteins that create a pore to connect cells
Which of the following describes passive transport?
It does not require an expenditure of energy by the cell itself.
Tight junctions
Leak-proof seal that surrounds the cell
Which of the following are distinctly different in archaeal cells as compared to bacterial cells?
Lipids
Which of the following is the largest organelle present in eukaryotic cells?
Nucleus
Which of the following makes up the bilayer of every cell membrane?
Phospholipids
Which of the following can relatively easily move laterally within the plasma membrane?
Phospholipids and unanchored proteins
Which of the following junction types is only found in plants?
Plasmodesmata
Which of the following transport proteins use energy from ATP directly?
Protein pumps
The production of proteins is achieved by which of the following structures?
Ribosomes
Substances that cannot easily cross the lipid bilayer can still diffuse across the plasma membrane with the help of which of the following?
Specific channel proteins or carrier proteins
The ER membrane is typically thinner and more fluid than the plasma membrane and it contains more curvature. Why?
The ER membrane contains mainly unsaturated phospholipids.
Which is the largest of the internal membranes in a typical eukaryotic cell?
The endoplasmic reticulum
When phospholipids are placed in water, they spontaneously form a bilayer. Why?
The polar heads on the surface of the bilayer interact with water, while the nonpolar tails in the interior of the bilayer do not come into contact with water.
Which of the following is a defining feature of biological membranes?
The presence of two phospholipid sheets
This diagram shows two solutions separated by a membrane that allows water to pass through freely but prevents the passage of urea. Before equilibrium is reached, which statement is true?
The solution on the right has a higher concentration of free water molecules.
If two solutions have unequal concentrations of solutes, which one will be considered hypertonic?
The solution with the higher solute concentration
Coupled transport proteins (CTP) use a gradient that is generated by another protein. The gradient generating protein is using ATP.
Therefore the CTP is using the energy from ATP indirectly.
Which statement accurately describes bacterial flagella?
They consist of protein rings embedded in the plasma membrane and the cell wall with long fibers extending from them.
Select the statement that is true of transmembrane domains.
Transmembrane domains are composed of hydrophobic amino acids.
What is the name of carrier proteins that transport a single type of molecule or ion?
Uniporters
Eukaryotic flagella are actually outward projections of the cell's interior. The microtubules in the flagella originate from
a basal body
If you compare two aqueous solutions which differ in the amount of solutes dissolved, the aqueous solution with a higher concentration of solutes will have
a lower concentration of free water molecules
exocytosis
a process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane with the cell membrane.
Which fiber is involved in cellular crawling?
actin
The main types of cytoskeletal fibers are ___________ filaments (also known as microfilaments), intermediate filaments and ______________
actin ; microtubules
The main types of cytoskeletal fibers are _____________ filaments (also known as microfilaments), intermediate filaments and _________________.
actin ; microtubules
While ___________transport requires the cell to expend some of its own energy, ____________transport does not.
active ; passive
A solution where water is the solvent is called a(n) ___________ solution.
aqueous
Prokaryotes are found in two domains:
bacteria and archaea
The microtubules in a eukaryotic flagellum are derived from a(n)
basal body
The two main categories of __________ __________are endocytosis and exocytosis.
bulk transport
Adherens junctions can be found in the cells of vertebrates and invertebrates and are based on the protein
cadherin
Of the 2 types of transport proteins that mediate facilitated diffusion, ___________ proteins actually bind with the substance being transported, while ______________ proteins simply provide a hydrophilic space for the substance to move through.
carrier ; channel
Of the 2 types of transport proteins that mediate facilitated diffusion, _____________ proteins actually bind with the substance being transported, while _______________ proteins simply provide a hydrophilic space for the substance to move through.
carrier ; channel
Antiporters
carry two substances across the membrane in opposite directions
Symporters
carry two substances across the membrane in the same direction
Cells that are part of the same tissue type recognize each other based on
cell-surface markers
The cell walls of plants and protists are made of the polysaccharide ___________ while the cell wall of fungal cells are made of the polysaccharide _______________
cellulose ; chitin
The cell walls of plants and protists are made of the polysaccharide _____________ while the cell wall of fungal cells are made of the polysaccharide _________________.
cellulose ; chitin
Many substances that are repelled by the hydrophobic interior of the lipid bilayer can readily diffuse across the plasma membrane with the help of specific ___________ proteins or ____________ proteins. These transporter proteins are typically transmembrane proteins.
channel ; carrier
Ion ____________ have a hydrated interior that spans the membrane and allows ions to diffuse through.
channels
In plants, photosynthesis occurs in semiautonomous organelles called
chloroplasts
The of the Golgi apparatus are flattened, stacked membrane folds.
cisternae
The internal portion of the endoplasmic reticulum is known as the __________ space or, ___________
cisternal ; lumen
The fibrous protein, ____________, found in the extracellular matrix of animal cells, is also a major component of cartilage and tendons.
collagen
The inner folded membrane of the mitochondria has numerous contiguous layers called
cristae
Due to the constant random motion of its atoms and molecules, a substance will exhibit net movement from a region where it has a higher concentration to a region where it has a lower concentration. This net movement is called
diffusion
Each membrane-spanning region of a transmembrane protein is called a transmembrane
domain
Phagocytosis is one of the three main types of
endocytosis
Based on the direction of movement, bulk transport can be divided into two main categories: ___________ and ____________.
endocytosis ; exocytosis
Eukaryotic cells achieve compartmentalization through an extensive _______________ system that weaves through the interior of the cell and by numerous membrane-bound ______________ that form compartments where biochemical processes can occur independently.
endomembrane ; organelles
Scientists have proposed that chloroplasts and mitochondria arose by a process called ____________, in which a smaller cell comes to live inside a larger cell.
endosymbiosis
Lipid synthesis occurs with the help of
enzymes embedded in the smooth ER.
In order to survive, grow, and reproduce, a cell must
exchange materials and information with its environment
The fusion of a secretory vesicle with the plasma membrane in order to discharge the contents of the vesicle is called
exocytosis
The reverse of endocytosis is
exocytosis
The long, threadlike structures protruding from the surface of bacteria are called
flagella
Cells continually exchange materials and information with their environment. This exchange is crucial
for all the processes occurring in a cell
Kary refers to the
genetic material
An aqueous solution with a lower concentration of solutes will have a ___________________ concentration of free water molecules.
higher
Passive transport occurs only when there is a concentration gradient and molecules/ions move from the side of the membrane with
higher concentration to the side with lower concentration.
Water is attracted to charged or polar solutes, forming ________ shells around them.
hydration
Water is attracted to charged or polar solutes, forming ___________ shells around them.
hydration
The space between the two membranes of a mitochondrion is known as the ________________ space
intermembrane
If two solutions have the same concentration of solutes (all solutes), they are __________ solutions.
isotonic or isosmotic
The lack of double bonds in phospholipids with saturated fatty acids allow them to pack together tightly, and therefore the membrane is _______________ fluid. Kinks introduced by double bonds in lipids with unsaturated fatty acids prevent them from packing together tightly, and therefore the membrane is ___________ fluid.
less ; more
The digestion of substances taken into the cell and the breakdown of old organelles in the cell are both performed by organelles called
lysosomes
Where does degradative enzymes destroy particles that the cell has ingested occur?
lysosomes.
Because of the kinks in chains fatty acids, phospholipids with unsaturated fatty acids tend to
make the membrane more fluid.
Surface ____________ give cells their identity. In multicellular organisms, this allows the recognition of cells that are of the same tissue type.
markers, lipids, glycolipids, or proteins
Cellular ___________ are said to be selectively _____________ because they allow some substances to pass through easily while other substances pass through very slowly or not at all.
membranes ; permeable
Centrosomes, also called _____________ -organizing centers, are important for cell division in animals.
microtubule
The organelles that are both surrounded by a double membrane, have their own DNA, are involved in energy metabolism, and have their own protein synthesis machinery are the ___________ and __________
mitochondria/mitochondrion ; chloroplasts
Golgi functions in
modifying and sorting proteins to their correct target destination
Myosin functions as a
motor protein to move cargo along actin filaments
The diffusion of water across a selectively permeable membrane is called
osmosis
Exocytosis is the bulk transport of substances
out of the cell.
Transport that occurs without a cell expending any of its own energy is called __________ transport.
passive
Most bacterial cells are encased by a strong cell wall composed of________________ which is a carbohydrate matrix cross-linked by polypeptides.
peptidoglycan ; murein
Functions that include glycoprotein production and protein sorting are characteristic of the _________ endoplasmic reticulum.
rough
During facilitated diffusion by carrier proteins, when solute concentrations are low, increasing the solute concentration causes a linear increase in the rate of diffusion. However, at high solute concentrations, further increases in the solute concentration no longer increase the rate of diffusion. This means that carrier proteins exhibit
saturation
In addition to storing lipids for energy metabolism, lipid droplets can act as
secondary sites of lipid synthesis
A partially permeable membrane would allow similar molecules to pass through without discriminating between them. Because the cell uses proteins to transport molecules through the membrane and those proteins only transport specific molecules, the membrane is said to be
selective.
Plasma membranes allow some substances to pass through easily while other substances only pass through very slowly or not at all. For that reason, plasma membranes are said to be
selectively permeable
Functions that include steroid synthesis and assembly of membrane lipids are characteristic of the _________ endoplasmic reticulum
smooth
Ca2+ ions are stored in the __________ endoplasmic ___________
smooth ; reticulum
The sodium-potassium pump actively pumps
sodium ions out of the cell and potassium ions into the cell
When 10 grams of NaCl are dissolved in 1 L of water, NaCl is called the ____________ and water is called the ____________.
solute ; solvent
Although a eukaryotic cell membrane can contain many different lipids, they can be classified in three groups: glycerol phospholipids, _____________ , and ______________.
sphingolipids ; sterols
Although a eukaryotic cell membrane can contain many different lipids, they can be classified in three groups: glycerol phospholipids, ________________ , and _______________.
sphingolipids ; sterols
Carrier proteins that transport 2 different types of molecules or ions may be either ___________ or antiporters.
symporters
Where does proteins are modified before being transported to other locations occur
the Golgi apparatus.
Oxygen is a small non-polar molecule and can diffuse into the cell without the need for a transport protein. Oxygen-binding proteins like hemoglobin do not
transport oxygen across the membrane. They increase the effective concentration of oxygen (which has a very low solubility).
microtubules are made of
tubulin, and they are essential in chromosome movement during mitosis. Microtubules are big
The central _________ of a plant cell is involved in maintaining the tonicity of the cell
vacuole
In an aqueous solution the solvent is
water
Osmosis occurs when there is a selectively permeable membrane and it refers to the diffusion of
water
The cytoplasm contains ions and molecules dissolved in
water
The most abundant molecule in the cytoplasm is the ______________ molecule.
water
When 10 grams of sugar are dissolved in 1 L of water, __________ is the solvent and _____________ is the solute.
water ; sugar
