Block 1 - Cells

Question 1

All eukaryotic cells possess these three structures?

Answer 1

Plasma membrane (plasmalemma); cytoplasm: a gelatin-like substance plus the structural fibers and organelles; nucleus: contains genetic library of the cell

Question 2

The plasma membrane is considered what type of barrier?

The plasma membrane plays a role in what type of communication?

Answer 2

selectively permeable barrier

cellular communication

Question 3

Within the cytoplasms, organelles are subcellular structures that are embedded in what?

Answer 3

cytosol

Question 4

What large cellular organelle contains DNA within chromosomes?

Answer 4

Nucleus

Question 5

What portion of the cell is fluid but relatively stable and made up of a phospholipid bilayer with associated integral and peripheral proteins?

Answer 5

plasma membrane

Question 6

The arrangement of molecules within the plasma membrane is referred to what term?

Answer 6

the Fluid Mosiac Model

Question 7

A “fluid” plasma membrane provides and allows for:
A. ______________
B. ______________

Answer 7

cell movement, growth, division, etc.

self-sealing if torn or punctured

Question 8

A lipid membrane allows for what type of substances to pass through the membrane?

What is a lipid membrane a barrier to?

Answer 8

lipid-soluble substances

barrier to passage of charged or polar substances

Question 9

A lipid bilayer is considered _________, or having both polar and nonpolar parts.

Phosphate containing heads are ________.
Fatty acid tails are __________.

Answer 9

amphipathic

polar
nonpolar

Question 10

What three molecules make up a lipid bilayer?

Answer 10

phospholipids, cholersterol, glycolipds

Question 11

What portion of the bilayer “mediates fluidity”?

What portion of the molecule is it’s “polar part”?

This portion forms _______ _____ with the heads of phospholipids and glycolipds and fills the space etween fatty acid tails.

Answer 11

cholesterol

-OH (-ol=tells you it’s an alchohol)

hydrogen bonds

Question 12

What substances for the lipid bilayer of the plasma membrane?

Answer 12

phospholipids, cholesterol, glycolipids

Question 13

What type of protein extends into or through the bilayer?

What type of protein spans the entire lipid bilayer?

What type of protein attaches to the inner or outer surface but do not extend through the membrane?

These membrane proteins have a carbohydrate group attached that protrudes into the extracellular fluid.

Answer 13

integral proteins

transmembrane proteins (most integral proteins)

peripheral

glycoproteins

Question 14

The entire “sugary coating” surrounding the membrane (made up of the carbohydrate portions of the glycolipids/glycoproteins?

Answer 14

the glycocalyx

Question 16

Membrane proteins can be classified as what two types?

Describe their general function (if applicable).

Answer 16

integral: extends through
(transmembrane proteins extend all the way through)
form ion channels (channel proteins)
transporters (carriers)

peripheral: on one side of the membrane
attached to the phospholipd heads or to integral proteins

Question 17

Within the functions of the membrane, describe each.

a. “some integral proteins”
b. selectively move substances through the membrane
c. for cellular recognition
d. catalyze chemical reactions-others, act as cell-identity markers

What does a ligand do?

Answer 17

integral proteins are ion channels

transporters selectively move substances through the membrane

receptors for cellular recognition

enzymes catalyze chemical reactions; others act as cell-identity markers

A ligand binds to a receptor however it will cause a change within the cell.

Question 18

Describe the three integral membrane proteins.

Answer 18

ion channels: allows specific ion to move through water-filled pore. Most plasma membranes include specific channels for several common ions.

carriers: carries specific substances across membrane by changing shape. Carriers are also known as transporters.

receptors: recognizes specific ligands and alters cell’s function in some way.

Question 19

Define and describe the two integral and peripheral membrane protein.

Answer 19

Enzymes: catalyzes reaction inside or outside of a cell.

Linker: Anchors filaments inside and outside the plasma membrane; providing structure and shape for the cell. Can participate in the movement of the cell or link two cells together.

Question 20

What is a plasma membrane protein that distinguishes your cells from someone elses (unless you are an identical twin)?

Answer 20

cell-identity marker (MHC protein/glycoprotein)

Question 21

What exists only on the outer face of the plasma membrane and is comprised of glycoproteins and glycolipids?

Answer 21

The glycocalyx

Question 22

What protects the cell from enzymatic action, cell adhesion, and cell recognition?

Answer 22

the glycocalyx

Question 23

Changes in this cell structure occurs when cells are transformed into cancer cells.

Answer 23

glycocalyx

Question 24

Due to the array and distributions of lipids and proteins embedded in it, this membrane only allows some substances across it-but not others.

Answer 24

a selective permeable membrane

Question 25

True or False: Transmembrane protein channels and carriers selectively decrease membrane permeability to ions and molecules that cannot cross the lipid bilayer unassisted.

Answer 25

False; increase

Question 26

What is the other name for a selectively permeable membrane?

Answer 26

differentially permeable

Question 27

What are some substances that are nonpolar and lipid soluble that move in and out of the cell by simple diffusion through the plasmalemma?

Answer 27

Oxygen carbon dioxide fats, alcohol fat-soluble vitamins (A, D, E, K)

Question 28

Molecules can passively diffuse through the plasma membrane if they are?

Answer 28

Lipid soluble Small enough to pass through membrane pores Assisted by carrier molecules

Question 29

What are the three types of gradients? Define each.

Answer 29

**Concentration**: the attribute is concentration of a chemical **Electrical**: attribute is electrical charges **Electrochemical**: combined influence of the above two

Question 30

What molecule and ions are more concentrated in the extracellular fluid than in cytosol?

Answer 30

Oxygen molecules Sodium ions

Question 31

What molecule and ions are more concentrated in the cytosol than in the extracellular fluid?

Answer 31

carbon dioxide potassium ions

Question 32

The external of the cell carries a _______ charge; while the internal of the cell carries a ________ charge.

Answer 32

``` external = positive internal = negative ```

Question 33

Movement of materials through the plasma membrane takes place by what two processes? Describe each.

Answer 33

_**Active**:_ (energy required) * **Active* transport**: primary / secondary * **Bulk* transport**: exocytosis, endocytosis, transcytosis * *_Passive_**: (no energy required) * *Diffusion**: simple diffusion, osmosis, facilitated diffusion * *Filtration**

Question 34

What is a process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole mebrane with the cell membrane? What is the taking in of matter by a living cell by invagination of its membrane to form a vacuole? What is a type of transcellular transport in which various macromolecules are transported across the interior of a cell?

Answer 34

exocytosis endocytosis transcytosis

Question 35

True or False: The passive spread of particles through random motion from areas of low concentration to areas of high concentration.

Answer 35

False; they move from high to low

Question 36

Osmosis is an example of what type of gradient?

Answer 36

concentration gradient

Question 37

Tonicity is a characteristic of a \_\_\_\_\_\_\_\_\_\_.

Answer 37

a solution

Question 38

Tonicity is the measure of the solution's ability to change a cell's _______ content by induction of osmosis.

Answer 38

water

Question 39

What three types of tonicity of a solution are there?

Answer 39

isotonic, hypotonic, hypertonic

Question 40

In terms of tonicity, what is the term for each respective definition? There are equal concentrations of osmotically active solutes. There is a lower concentration than the cell, less able than the cell to influence water movement, so water moves *into* the cell. There is a higher concentration, more influence than the cell, so water moves *out* of the cell.

Answer 40

isotonic (iso-isolate / stays the same) hypotonic (hypo (say it out loud and your lips will form an "oh" just as the cell swells) hypertonic (hyper (say it out loud and your lips form an "uhr" just as the cells shrink, so do your lips.)

Question 41

For molecules undergoing this type of diffusion, the solute binds to a protein carrier on one side of the membrane and is released on the other side after the carrier/transporter undergoes a change in shape?

Answer 41

facilitated diffusion

Question 42

What must be present in passive diffusion?

Answer 42

There has to be a concentration gradient in passive diffusion.

Question 43

In facilitated diffusion, what occurs when the concentration becomes equal on both sides of the membrane and net movement ceases?

Answer 43

a state of dynamic equilibrium is attained

Question 44

What are the two types of active transport?

Answer 44

primary and secondary active transport

Question 45

A sodium-potassium pump is an example of what type of transport?

Answer 45

primary active transport

Question 46

Sodium potassium pumps operate all the time in living cells to maintain the concentration gradient of high ___ and low ____ inside the cell.

Answer 46

K+ , Na+

Question 47

In secondary active transport, the energy stored in a Na+ or H+ concentration gradient is used to drive other substances across the membrane against their concentration gradient. The secondary active transport indirectly uses energy obtained from what process?

Answer 47

the hydrolysis of ATP.

Question 48

Within secondary active transport, there are two mechanisms. Define each and explain.

Answer 48

**Antiporters**: carry two substances across the membrane in opposite direction (anti=opposite, porter=carry) **Symporters**: carry two substances across the membrane in the same direction (sym=same, porter=carry))

Question 49

A small spherical sac formed by budding off from a membrane.

Answer 49

vesicle

Question 50

What are the three types of endocytosis?

Answer 50

A. receptor-mediated endocytosis B. phagocytosis C. bulk-phase endocytosis (pinocytosis)

Question 51

True or False: Energy is not required for vesicular transport.

Answer 51

False; it is a form of active transport.

Question 52

What is specifically needed for receptor-mediated endocytosis?

Answer 52

a specific ligand

Question 53

What bulk-phase endocytosis type is roughly translated into "cell drinking"?

Answer 53

pinocytosis

Question 54

What form of endocytosis engulfs large solid particles such as worn-out cells, bacteria, and viruses?

Answer 54

phagocytosis

Question 55

In what cells does exocytosis occur?

Answer 55

secretory cells that prouce substances such as digestive enzymes, hormones, mucus, etc. nerve cells, which release neurotransmitters

Question 56

What process most often occurs across endothelial cell lining blood vessels whereinmaterials are moved between the blood plasma and interstitial fluid?

Answer 56

transcytosis

Question 57

What serves as structural framework, that provides for cellular movement, by providing a scaffold comprised of these three structures?

Answer 57

cytoskeleton microfilaments intermediate filaments microtubules

Question 58

**What is the term for the definition?** A double membrane that separates the nucleus from the cytoplasm. The numerous openings in the nuclear envelope, control movement of substances between nucleus and cytoplasm. A spherical body that produced ribosomes. The cells hereditary units, control activities and structure of the cell. Long molecules of DNA combined with protein molecules.

Answer 58

nuclear envelope nuclear pores nucleolus genes chromosomes

Question 59

What structure of the cells are a part of a dense complex of RNA / DNA / protein?

Answer 59

nucleolus

Question 60

Where does the nucleolus form? What does it produce?

Answer 60

It forms around the portions of certain chromosomes having regions that code for production of ribosomes. Produces both ribosomal subunits

Question 61

What is a complex of DNA and proteins - represents the relaxed, uncoiled chromosomes of the interphase nucleus?

Answer 61

chromatin

Question 62

Where are ribosomes made?

Answer 62

In the nucleolus

Question 63

Ribosomes are where amino acids are assembled into what molecule? Ribosomes are composed of two subunits: what are they? Are they permanently associated? What two forms do ribosomes exist?

Answer 63

proteins large and small; not permanently associated * *Free** = *loose* in the cytosol * *Attached** = temporarily *attached* to a membrane

Question 64

The two ribosomal subunits reside, disassembled in the cytoplasm. The large subunit joins the amino acid and forms a ___________ \_\_\_\_\_\_\_\_. The small subunits initiates translation, recruits the large ribosomal subunit, and reads the mRNA, which does what?

Answer 64

polypeptide chain determines the primary sequence of amino acid comprising the protein

Question 65

Endoplasmic reticulum is an extensive network of _________ running throughout the cell. The two types of ER are: The two types are continuous with each other and with the nuclear \_\_\_\_\_\_\_\_\_\_.

Answer 65

membranes Smooth ER: ER without ribosomes Rough ER: ER with ribosomes envelope

Question 66

Rough ER is more \_\_\_\_\_\_\_. Smooth ER is a network of \_\_\_\_\_\_\_\_\_.

Answer 66

linear network of tubules

Question 67

The Golgi complex is a stack of 3-20 flattened, membraned-enclosed sacs called \_\_\_\_\_\_\_\_\_\_\_. Transport vesicles arriving from the rough ER fuse with the ____ face of the Golgi. Secretory vesicles, lysosomes, and peroxisomes bud from the ____ face of the Golgi.

Answer 67

cisternae cis trans

Question 68

What is the function of the Golgi complex?

Answer 68

receives "immature" proteins from the rough ER packages proteins into vesicles synthesizes carbohydrates "*packaging and export mechanism for the cell"*

Question 69

What are the three destinations for the proteins that leave the Golgi complex? Explain each.

Answer 69

**Secretory** vesicles: wherein the proteins will be *exported (secreted)* from the cell by exocytosis **Membrane** vesicles: wherein the proteins in the vesicle membranes *merge* with the plasma membrane **Transport** vesicles: in which the proteins (some of which are enzymes) are *conveyed* to such structures as lysosomes, or to other parts of the cell

Question 70

How many membranes does the mitochondria have? Which layer produces cristae? Mitochondria replicate in what manner? The mitochondria contains enzymes for what two cellular processes? Most of the cell's ______ is produced here.

Answer 70

2 the inner layer produces cristae self-replicating cellular respiration and the krebs cycle ATP

Question 71

True or False: Mitochondria have their own ribosomes.

Answer 71

True

Question 72

What are the vesicles that form from the Golgi complex and contain powerful digestive enzymes? What is their function?

Answer 72

**Lysosomes** digest substances that enter a cell via endocytosis then transport products of digestion into the cytosol carry out autophagy (the digestion of worn-out organelles) carry out autolysis, the digestion of the entire cell

Question 73

What are the Golgi complex products that detoxify several toxic substances and are abundant in the liver? These structures also break down a byproduct of oxidation using the enzyme catalase. What is the byproduct? These structures are also self-replicating but do not possess DNA.

Answer 73

peroxisomes H2O2

Question 74

These portions continuously degrade (destroy) unneeded, damaged, or faulty proteins and are found in the cytosol and the nucleus. These structures are membranous sacs within the cytoplasm of cells; commonly formed when part of the plasma membrane folds inward and pinches off during phagocytosis.

Answer 74

proteasomes vacuoles

Question 75

These structures assemble microtubules near the nucleus and are comprised of 9 microtubule triplets.

Answer 75

centrosome

Question 76

What is a group of diseases characterized by uncontrolled or abnormal cell proliferation? What is the term for excess tissue that develops as the result of cancer? What is the medical study of tumors? What is the term for the spread of cancerous cells to other parts of the body? What is the term for a cancerous neoplasm that tends to metastasize?

Answer 76

cancer tumor/neoplasm oncology malignancy metastasis