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Mol / Cel Biology > Lecture 10 > Flashcards

Lecture 10 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Endomembrane system includes:

A 
Nuclear envelope,
The endoplasmic reticulum (ER),
Golgi apparatus,
Lysosomes,
Vesicles.
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2
Q

Rough ER functions:

A

Site for protein synthesis;

Protein translocation, folding
and transport;

Glycosylation (addition of sugar groups;

Stabilize the tertiary and
quaternary structures of
proteins.

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3
Q

Smooth ER functions:

A

Lipid synthesis;

Glycogen synthesis;

Synthesis of steroid hormones
(e.g. gonads);

Metabolism of carbohydrates;

Detoxification function (e.g.
liver cells);

Major storage and released site
of calcium ions (e.g. muscle
cells).

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4
Q

Functions of Golgi apparatus

A

Protein sorting and export;

Protein glycosylation;

Lipid and polysaccharide metabolism and transport;

Formation of lysosomes.

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5
Q

Lysosomes are (waste crap :)):

A

Function in destruction of cell`s own organelles and their replacement – autophagy.

Take part in phagocytosis.

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6
Q

Lipids are:

A

Amphipathic molecules – consist of polar (hydrophilic)

head group and hydrophobic tail.

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7
Q

The head group is the ______ and an _____ (serine,
ethanolamine, inositol, or choline) = phosphatidylcholine,
phosphatidylserine, phosphatidylethanolamine etc.

A

phosphate

alcohol

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8
Q

Sphingolipids are derived from:

A

Sphingosine (amino alcohol).

Contain a long-chain fatty acid attached to the sphingosine amino group.

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9
Q

Glycosphingolipids:

A

polar head groups are sugars. 2–10 % of the total lipid in plasma membranes (most abundant in nervous tissue).

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10
Q

Sterols are:

A

They are amphipathic lipids synthesized from acetyl-coenzyme. The basic structure is a four-ring hydrocarbon.

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11
Q

Cholesterol:

A

is especially abundant in the plasma

membranes of mammalian cells.

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12
Q

Integral membrane proteins (transmembrane proteins) (where they are and what they do?)

A

Span a phospholipid bilayer. The cytosolic and exoplasmic domains have hydrophilic exterior surfaces. The membrane-spanning domain contains many hydrophobic amino acids.

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13
Q

Lipid-anchored membrane proteins bounds?

A

Covalently to one or more lipid molecules.

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14
Q

Peripheral membrane proteins do not interact with?

A

The hydrophobic core of the phospholipid bilayer, localized to either the cytosolic or the exoplasmic face of the plasma membrane.

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15
Q

Transmembrane proteins contain carbohydrate……?

A

Carbohydrate chains, they are always located in the exoplasmic face of membrane and are available to interact with components of the extracellular matrix as well as growth factors and antibodies.

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16
Q

Functions of plasma membrane:

A

Compartmentalization.

Scaffold for biochemical activities.

Prevent unrestricted movement of molecules.

Transport of solutes.

Response to external stimuli - involved in the signal
transduction.

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17
Q

Small molecules are:

A

Water, inorganic ions, and relatively small organic

molecules (e.g., sugars, vitamins, fatty acids) account for 75 – 80 % of living matter by weight.

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18
Q

Functions of small molecules:

A

Function as precursors for synthesis of macromolecules.

Store and distribute the energy for all cellular processes.

Signalling function.

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19
Q

The plasma membrane is ______ ______ to small molecules.

A

selectively permeable

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20
Q

Transport of small molecules are defined by molecules:

A

Size, change, solubility.

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21
Q

Passive (simple) diffusion means:

A

Molecule dissolves in the phospholipid bilayer, diffuses across it, and then dissolves in the aqueous solution at the other side of the membrane.

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22
Q

The direction of transport is determined by:

A

The relative concentrations of the molecule inside and outside of the cell.

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23
Q

The transport reactions are (chemistry):

A

Spontaneous because they have a positive delta S value (increase in entropy) and thus a negative delta G (decrease in free energy).

24
Q

Facilitated diffusion is (passive transport still!):

A

Allows polar and charged molecules, such as
carbohydrates, amino acids, nucleosides, and ions, to cross the plasma membrane.
Is always energetically downhill.

25
Q

Carrier proteins are:

A

Membrane carrier protein that binds to a solute and
transports it across the hydrophobic regions of the
membrane.

26
Q

All carrier proteins are (what proteins)?:

A

Transmembrane proteins containing multiple membrane-spanning segments.

27
Q

Uniported carrier proteins:

A 
Transport a single type of molecule down its
concentration gradient (glucose and amino acids).
28
Q

Channel proteins forms?

A

Hydrophilic passageway.
Open pores in the membrane, allowing small molecules of the appropriate size and charge to move through the lipid bilayer.

29
Q

Channel proteins transport water or specific types of:

A

ions and hydrophilic small molecules down their concentration or electric potential gradients.

30
Q

Ion channel properties are:

A

Transport through channels is extremely rapid.

Ion channels are highly selective because narrow pores in the channel restrict passage to ions of the appropriate size and charge.

31
Q

Non-gated ion channels are:

A

permanently open.

32
Q

Gated ion channels are:

A

not permanently open.

33
Q

In active transport, energy provided by:

A

another coupled reaction (such as the hydrolysis of ATP) is used to drive the uphill transport of molecules in the energetically unfavourable direction

34
Q

ATP-powered pumps are:

A

ATPases that use the energy of ATP hydrolysis to move ions or small molecules across a membrane against a chemical concentration gradient or electric potential or both.

35
Q

What are macromolecules?

A

A large complex molecules, such as nucleic acids, proteins, carbohydrates, and lipids, with relatively large molecular weight.

36
Q

Can transmembrane proteins carry macromolecules?

A

No. Transmembrane proteins, carrier proteins and pumps are not able to ensure transport of macromolecules.

37
Q

What is endocytosis?

A

Process in which eukaryotic cells are able to take up macromolecules and particles from the surrounding. The uptake of extracellular material in
vesicles formed from the plasma membrane.

38
Q

Pinocytosis:

A

Type of endocytosis in which soluble materials are taken up from the environment and incorporated into vesicles for digestion.

39
Q

Receptor mediated endocytosis -> Phagocytosis:

A

A special form of endocytosis in which large particles such as microorganisms and dead cells are transported into the cell via large endocytic vesicles called phagosomes.

40
Q

Binding of particle to receptors on the surface of cell

triggers the?

A

extension of pseudopodia (actin-based

movement of the cell surface).

41
Q

Fusion of pseudopodia forms?

A

Phagosome. The phagosomes then fuse with lysosomes, producing phagolysosomes.

42
Q

Receptor mediated endocytosis are:

A

The selective uptake of macromolecules that bind to cell surface receptors. Receptors are concentrated in clathrincoated pits.

43
Q

What is clathrin?

A

Specific region of plasma membrane is coated with the
protein clathrin on its cytosolic face.
Such regions are continually forming and budding off by endocytosis to form intracellular clathrin-coated vesicles containing extracellular fluid and the materials dissolved in it

44
Q

Exocytosis:

A

Exocytosis is the process by which the cell secreted

molecules are released into the extracellular fluid.

45
Q

Constitutive exocytosis:

A

Carried out by all cells and serves to transfer molecules from the Golgi network to the outer surface of the cell.

46
Q

Most proteins are transported directly to the cell surface by (exocytosis):

A

the nonselective constitutive secretory pathway (does not require a particular signal)

47
Q

Regulated exocytosis:

A

Regulated secretion occurs in response to specific
conditions, signals or biochemical triggers.

It is the process underlying the release of cytokines, hormones, neurotransmitters and other small signalling molecules!!!

48
Q

Secretory proteins are packed into:

A

secretory vesicles.

49
Q

Secretory vesicle fuses with the:

A

plasma membrane, contents are discharged from the cell by exocytosis, and its membrane becomes part of the plasma membrane.

50
Q

The assembly of the coat helps to collect:

A

specific membrane and soluble cargo molecules for transport and to drive the formation of the vesicle.

51
Q

Diversity of vesicles, example:

A

Clathrin-coated vesicles.
COPI- and COPII-coated vesicles.

Before the vesicle fuses with a target membrane, the coat is discarded, to allow the two cytosolic membrane
surfaces to interact directly and fuse.

52
Q

Which one of the transport:

Requires specific protein: No
Solute transport against its gradient: No
Coupled to ATP hydrolysis: No
Driven by movement of a contransport ion down its gradient: No

A

Passive diffusion.

Examples: gasses, steroid hormones, many drugs!

53
Q

Which one of the transport:

Requires specific protein: Yes
Solute transport against its gradient: No
Coupled to ATP hydrolysis: No
Driven by movement of a contransport ion down its gradient: No

A

Facilitated diffusion.
Examples: Glucose and amino acids (uniporters),
Ions and water (channels)

54
Q

Which one of the transport:

Requires specific protein: Yes
Solute transport against its gradient: Yes
Coupled to ATP hydrolysis: YES
Driven by movement of a contransport ion down its gradient: No

A

Active transport.

Examples: Ions, small hydrophilic molecules, lipids (ATP-powered pumps)

55
Q

Which one of the transport:

Requires specific protein: Yes
Solute transport against its gradient: Yes
Coupled to ATP hydrolysis: NO
Driven by movement of a contransport ion down its gradient: YES

A

Cotransport (secondary active transport).

Glucose and amino acids (symporters), various ions and sucrose (antiporter)

56
Q

Uniporter belongs to category of:

A

Facilitated diffusion. Transports a single molecule down its concentration gradient.

57
Q

Cotransporters belongs to category of:

A

Symporter and antiporter.

In active transport, energy provided by another coupled reaction (such as the hydrolysis of ATP) is used to drive the uphill transport of molecules in the energetically unfavourable direction.

Mol / Cel Biology (17 decks)

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