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anatomy > week 2 > Flashcards

week 2 Flashcards

1
Q

The Cell Theory

A

A cell is the basic structural and functional unit of all organisms.
The biochemical reactions occurring in a cell are dictated by the subcellular structures present in the cell.

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2
Q

3 main parts of a cell

A

plasma membrane, cytoplasm, nucleus

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3
Q

What embedded in the lipid bilayer of the plasma membrane?

A

membrane proteins and cholesterol

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4
Q

Fluid Mosaic Model

A

Lipid bilayer exhibits fluidity, and the membrane proteins are in
constant flux - their shapes constantly change as in a kaleidoscope or a mosaic pattern.

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5
Q

Cholesterol importance in Plasma Membrane

A

Cholesterol inserts between the phospholipids tails to stabilize the
plasma membrane = “ cholesterol therefore maintains the integrity of the plasma membrane

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6
Q

Integral proteins

A

Span the plasma membrane exposed on one surface or both
surfaces of the plasma membrane.
Integral proteins exposed on both surface of the plasma membrane are called Transmembrane Proteins

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7
Q

Peripheral proteins

A

attached to integral proteins or the phospholipids’ heads on the
extracellular face of the plasma membrane

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8
Q

6 functions of membrane functions

A

Transport, enzymatic activity, receptors, intercellular joining, cell-cell recognition, attachment to cytoskeleton & extracellular matrix

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9
Q

Tight junction

A

Fusion of integral proteins in plasma
membrane of adjacent cells that prevent the transfer of substances
directly between adjacent cells hence, tight junctions are also
known “impermeable junctions”

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10
Q

Desmosome

A

linker proteins extending from plaques on the cytoplasmic surface of the plasma membrane of adjacent cells interdigitate to hold the cells together and prevent their
separation. Desmosomes are also known as “anchoring junctions”

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11
Q

Gap Junction

A

Formed by hollow cylinder called connexon; it allows for the rapid transfer of ions between cells; Gap junctions also known as “communicating junctions”. Cells connected by gap junctions are electrically-coupled

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12
Q

Passive processes
two types…

A

substances cross the plasma membrane without any energy input. There are two types: diffusion and filtration.

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13
Q

diffusion
3 subtypes..

A

movement of substances from area of higher concentration to area of lower concentration = down a concentration gradient
3 subtypes: simple diffusion
facilitated diffusion
osmosis

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14
Q

filtration

A

A passive process: no energy input. Movement of solution from area of higher pressure to area of lower
pressure = down a pressure gradient
Filtration occurs in the kidneys as the first process in urine formation

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15
Q

Active processes

A

the cell provides energy required to move substances across
the plasma membrane
two types: active transport & vesicular transport

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16
Q

Active transport

A

movements of solute from area of lower concentration to area of
higher concentration against a concentration gradient hence, active transport is also known as “solute pumping”
active transport exhibits saturation and specificity
Ex. sodium./potassium pump ( Na+/K+ pump)

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17
Q

Exocytosis

A

movement of substances enclosed
in vesicles from the interior of cells to the exterior.
Protein secretion such as enzymes and hormones released from
endocrine cells are released via exocytosis; metabolic wastes are
secreted via exocytosis.

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18
Q

Simple diffusion

A

nonpolar/hydrophobic/lipid-soluble substances
diffuse through the plasma membrane. Ex. Oxygen, carbon dioxide

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19
Q

Facilitated diffusion

A

transport of large/polar substances mediated by
carrier proteins embedded in the plasma membrane.
Facilitated diffusion exhibits saturation and specificity

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20
Q

Osmosis

A

movement of water from area of lower solute concentration
to area of higher solute concentration through a semi-permeable
membrane. Water moves through specific pores in the plasma
membrane called aquaporins

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21
Q

isotonic solution

A

concentration of solution inside and
outside of the cells is the same; the same amount of water
moves in/out of the cells and thus, the shape of cells
remain unchanged

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22
Q

hypotonic solution

A

cells are placed in a solution with
a lower concentration than solution inside cells; water moves via osmosis into the cells – cells swell and
eventually lyse (burst)

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23
Q

hypertonic solution

A

cells placed in solution with a
higher concentration than solution inside cells; water
moves via osmosis from the cells; cell crenate ( shrink)

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24
Q

Endocytosis

A

movement of substances enclosed
in vesicles from the exterior of cells to the interior.
Nutrients, fluids, hormones taken into target cells, pathogens are
taken from the exterior into the interior of cells

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25
Q

Phagocytosis

A

movement of solid particles from the exterior into
the cell; solid particles such as clumps of bacteria or cell debris, are
enclosed in vesicles called PHAGOSOMES; Lysosomes fuse with
the phagosomes to digest the phagosomes and its contents.
**Only cells called phagocytes can perform phagocytosis

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26
Q

Pinocytosis

A

movement of
solution into cells by enclosing the solution in vesicles called
pinocytic vesicles. That’s how cells take in nutrients in bulk and
therefore all cells can perform pinocytosis

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27
Q

Receptor-mediated endocytosis

A

substances bind to specific
receptors (carrier-mediated) on the surface of the cell and taken into
the cell. ( LDL binds to LDL receptors on the surface of steroidogenic cells
and taken in via receptor mediated endocytosis; cholesterol is released
Receptor-mediated endocytosis exhibits saturation and specificity

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28
Q

Transcytosis

A

Movement
of substances enclosed in
vesicles into a cell via
endocytosis, travels across
the cell and released on the
opposite side of the cell via
exocytosis

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29
Q

Vesicular Trafficking

A

Intracellular movement of
substances in vesicles from
organelle to organelle
within the cell

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30
Q

The resting membrane potential (RMP)

A

RMP is established by the partial/selective permeability of the
plasma membrane to potassium ion (K+) diffusion over sodium ion
( Na+) diffusion.

31
Q

K & Na

A

K+ concentration is higher inside the cell than outside the cell –
K+ diffuses out of the cell down its electrochemical gradient
* Na+ concentration is higher outside of the cell than inside the cell
– Na+ diffuses into the cell down its electrochemical gradient
* The plasma membrane is about 75 times more permeable to K+
than Na+ = more K+ diffuses out of cell than Na+ diffusing into
the cell = more positive ions move out of the cell making the
cytoplasmic surface of the plasma membrane negative compared
to the extracellular surface

32
Q

Cytosol

A

the viscous, semitransparent fluid in which the
organelles are suspended

33
Q

Cytoplasmic organelles

A

specialized subcellular
compartments with specific functions
i) Mitochondria = “power plants”
ii) Ribosomes = sites of protein synthesis
iii) Endoplasmic reticulum ( ER)
Rough ER = “membrane factories”
Smooth ER = lipid/drug metabolism
iv) Golgi apparatus = “traffic director” of the cell
v) Lysosomes = “demolition crew”
vi) Peroxisomes = neutralize harmful free radicals
vii) Cytoskeleton = “skeleton” of the cell

34
Q

Membranous cytoplasmic organelles

A

organelles
surrounded by membranes
Mitochondria
Endoplasmic Reticulum (ER)
Golgi apparatus
Lysosomes
Peroxisomes

35
Q

Non membranous cytoplasmic organelles

A

not surrounded by membrane
Ribosomes
Cytoskeleton

36
Q

Mitochondria

A

Contain own DNA and are self-replicating organelles – when
the energy demands of a cell increases, its mitochondria
number increases by replication.
* Composed of 2 membranes enclosing a fluid matrix
* 2 mitochondrial membranes:
-outer membrane which appears featureless
- inner membrane consists of infoldings called
cristae

37
Q

Each ribosomal subunit consists of

A

protein and rRNA

38
Q

Free ribosomes

A

float freely in the cytosol and synthesize proteins that stay in the cell

39
Q

Bound ribosomes

A

bound to surface of rough ER and make proteins that are trasnported to the plasma membrane or for export out of the cell

40
Q

Rough ER

A

these ribosomes synthesize the
plasma proteins, enzymes enclosed in vesicles and
secretory proteins. Rough ER is therefore abundant in
secretory cells such as liver cells.
Rough ER is referred to as the “Membrane factory”
because the synthesis of plasma membrane proteins and
phospholipids which form the plasma membranes is
associated with the rough ER

41
Q

Smooth ER

A

Its membrane-bound enzymes
catalyze:
- Synthesis of fats, cholesterol
and the steroid hormones
– Detoxification of drugs and
carcinogens in liver and kidney
cells because, most drugs are
lipid-based

42
Q

Golgi Apparatus

A

Composed of stacked /flattened membranous sacs
* Receives proteins and lipids from the rough ER
* Golgi modifies, packages and tags proteins and lipids to their
specific destinations hence, the Golgi apparatus is referred to
as the “Traffic director” of the cell
* 3 types vesicles are released from the Golgi (next slide):
1) secretory vesicles which contain proteins released from the cell via
exocytosis
2) Vesicles that contain integral proteins and lipids destined for the
plasma membrane to incorporated into the plasma membrane.
3) Vesicles which are cytoplasmic organelles called LYSOSOMES-
contain powerful digestive enzymes called lysozymes (abundant
in phagocytes)

43
Q

lysosomes

A

Digest phagosomes hence,
lysosomes are abundant in
phagocytes
- Digest worn-out organelles
- Stimulate glycogenolysis
- Involved in bone resorption to
release calcium
Hence, lysosomes are referred to
as a cell’s “demolition crew”

44
Q

Peroxisomes

A

Contain powerful enzymes that neutralize harmful free radicals

45
Q

2 kinds of enzymes in peroxisomes

A

Oxidases and Catalases

46
Q

Although free radicals are
produced naturally in the body,
lifestyle factors can accelerate
their production. Those
include

A

exposure to toxic chemicals,
such as pesticides and air
pollution
*smoking
*alcohol

47
Q

What do peroxisomes do to free radicals

A

The enzymes in peroxisomes convert the harmful free radicals into the harmless compound,
water.
* In addition, the antioxidants, vitamins C and E neutralize free radicals by donating one of
their own electrons to stabilize free radicals.
* Free radicals have been involved in the pathogenesis of several diseases and in the aging
process

48
Q

Common Foods with the most antioxidants

A

Cranberries, blueberries, and blackberries ranked
highest among the fruits studied. Beans, artichokes, and Russet potatoes were tops
among the vegetables. Pecans, walnuts, and hazelnuts ranked highest in the nut
category.

49
Q

Cytoskeleton

A

he “Cell’s skeleton” – consists of non membranous rod-like
structures that support other cytoplasmic organelles and allow for
movements

50
Q

Microtubules

A

Largest cytoskeleton – hollow tubes composed of the globular
proteins called TUBULINS
* Radiate from the CENTROSOME which acts as a microtubule
organizing center

51
Q

Function of Microtubules

A

Serve as “tracks” to transport intracellular substances
- cytoplasmic organelles and secretory vesicles attached by motor
molecules to microtubules for intracellular, vesicular trafficking

52
Q

cilia

A

cellular extensions that occur in large numbers on the
apical ( exposed ) surface of cells
Several cells in the body are ciliated
* Cilia beat to create a unidirectional current that moves
substances across the surface of the cells

53
Q

Flagellum

A

a single, longer cellular extension
* Flagellum beats to propel the cell it extends from
* The only flagellated cell in the human body is sperm

54
Q

Intermediate Filaments

A

Composed of tough, insoluble fibrous fibers
* Most stable type of cytoskeleton
* Provide tensile strength to cells by resisting
pulling forces placed on the cells
* Given specific names in specific cell types:
Tonofilaments in epidermal cells
Neurofilaments in neurons

55
Q

Microfilaments

A

Have the smallest diameter
* Composed of the protein ACTIN
* The arrangement of microfilaments is unique to each
cell

56
Q

Function of Microfilaments

A

Involved in changes in cell shape or cell motility as in
contraction
Involved in the formation of cleavage furrow during
cytokinesis
Involved in the changes of the plasma membrane during
endocytosis and exocytosis

57
Q

3 regions of nucleus

A

Nuclear envelope (membrane)
* Nucleolus
* Chromatin

58
Q

Nuclear envelope

A

Double-layered selective membrane with nuclear pores
* Nuclear pores allow molecules to enter /exit the nucleus
– proteins translocate from the cytoplasm into the
nucleus; RNA molecules move from the nucleus into
the cytoplasm

59
Q

Nucleolus

A

Dark spherical non-
membranous structure in the
nucleus
Synthesizes ribosomal
RNA ( rRNA) required for
assembling the 2 ribosomal
subunits – small and large
Ribosomes are sites for
protein synthesis hence,
nucleoli are prominent in
cells producing large
amounts of proteins

60
Q

Chromatin

A

Chromatin is composed of
DNA and the histone proteins
* Consists of structural units
called NUCLEOSOMES
* Each nucleosome is composed of
8 globular histone proteins
connected by the thread-like
DNA

61
Q

Heterochromatin

A

condensed, inactive chromatin
with DNA wrapped around the
histone proteins
Type of chromatin

62
Q

Euchromatin

A

extended
type of chromatin

63
Q

Nucleic acids

A

2 Types of Nucleic Acids:
Deoxyribonucleic Acids = DNA
Ribonucleic Acids = RNA
They consist of structural units
called NUCLEOTIDES
Each nucleotide is composed of –
i) pentose sugar - deoxyribose or
ribose
ii) Nitrogen-containing base -
A,G, C, T, U
iii) Phosphate group

64
Q

Purines

A

Adenine “A”
Guanine “G

65
Q

Pyrimidines

A

Cytosine “C”
* Thymine “T”
* Uracil “U”

66
Q

SEMI-
CONSERVATIVE
REPLICATION

A

Each daughter DNA
consists of a an old
polynucleotide
strand and a newly-
synthesized
polynucleotide
strand

67
Q

Interphase

A

consists of 3 sequential phases: G1, S, G2
G1 phase – longest phase; protein synthesis; cell growth
S phase - DNA replication is the main event ( next slide)
G2 phase – protein synthesis especially those required for the
initiation/maintenance of mitosis

68
Q

Cell division

A

sequential phases: mitosis and cytokinesis
Mitosis – Nuclear division: 4 sequential subphases:
Prophase, Metaphase, Anaphase, Telophase
Cytokenesis – Cytoplasmic division

69
Q

Hyperplasia

A

Growth by increase in cell
number via mitosis

70
Q

hypertrophy

A

Growth by increase in cell
size

71
Q

Neoplasm

A

excessive proliferation of cells considered
abnormal

72
Q

Benign Neoplasm

A

grows slowly and it’s confined to
one location

73
Q

transcription

A

DNA is transcribed into pre mRNA; pre-mRNA is edited, intros are removed leaving exons= mRNA

74
Q

Translation

A

in cytoplasm, 3 base sequence on tRNA are called anti-codon

anatomy (8 decks)

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