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Anatomy and Physiology > Cellular Level of Organization > Flashcards

Cellular Level of Organization Flashcards

Chunk one, slides 2

1
Q

What is a cell? (4 things)

A
  1. Basic structural and functional unit of life.
  2. Smallest unit that performs all life functions.
  3. Comes from division of preexisting cells.
  4. Maintains homeostasis.
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2
Q

What are the two types of cells?

A

Somatic cells (soma = body):
all body cells except sex cells

Sex cells (germ; reproductive cells)
male sperms
female oocytes (eggs)

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3
Q

What are the general functions of the cell membrane?

A

1.Physical isolation (barrier)
2. Sensitivity to the environment
- extracellular fluid composition
- chemical signals
3. Regulates exchange with the environment
- Ions, nutrients, waste and cellular products
4. Structural support
- cell – cell
- cell - tissue

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4
Q

What are the percents of the cell membrane?

A

Lipids- 42%
Proteins- 55%
Carbohydrates- 3%

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5
Q

What do the lipids in the cell membrane make up?

A
  1. Phospholipid bilayer
    - hydrophilic heads:
    - toward environment, both sides
    - hydrophobic tails:
    - inside membrane
  2. Cholesterol
  3. Other lipids
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6
Q

What do the proteins in the cell membrane make up?

A
  1. Integral proteins
    - within the membrane
  2. Peripheral proteins
    - inner or outer surface of the membrane
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7
Q

What are the functions of membrane proteins? (6)

A

Cell-to-cell junctions
Enzymes
Transporters (channels and carriers)
Recognition
Anchors
Receptors

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8
Q

What do the carbohydrates in the cell membrane make up?

A
  1. Part of complex molecules:
    -e.g., glycolipids, glycoproteins & proteoglycans
  2. Glycocalyx (sugar coat):
    - carbohydrate part extends outside cell membrane
    - function:
    • anchoring and protection
    • lubrication and locomotion
    • specificity in binding (receptors)
    • recognition (immune response)
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9
Q

What are the functions of the cytoplasm?

A

All materials inside the cell and outside the nucleus:
- cytosol (intracellular fluid):
- dissolved materials (nutrients, ions, proteins, and waste products)
- organelles:
- structures with specific functions

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10
Q

Intracellular vs extracellular fluid

A

Sodium Ions (I)↓ (E)↑
Potassium Ions (I)↑ (E)↓
Proteins (I)↑ (E)↓
CHO, Fat, & Reserve AA (I)↑ (E)↓

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11
Q

What are nonmembranous organelles?

A
  • No membrane
  • Direct contact with the cytosol
    Organelles:
  • Cytoskeleton
  • Microvilli
  • Centrioles
  • Cilia
  • Ribosomes
  • Proteasomes
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12
Q

What are membranous organelles?

A
  • Covered with plasma membrane
  • Isolated from the cytosol
    Organelles:
  • Endoplasmic reticulum
  • Golgi apparatus
  • Lysosomes
  • Peroxisomes
  • Mitochondria
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13
Q

What is the cytoskeleton?

A
  • Backbone of the cell
  • Gives the cytoplasm strength & flexibility

Components:
- microfilamnets
- intermediate filaments
- thick filaments (only in muscle cells)
- microtubules

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14
Q

What are microfilaments?

A
  • Thin (<6 nm) filaments
  • Composed of the protein actin
    Function:
  • anchor the cytoskeleton to integral - - membrane proteins
  • Support microvilli
  • interact with thick filaments (myosin) to produce cellular movement
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15
Q

What are intermediate filaments?

A
  • Mid-sized (7-11 nm)
  • Composed of varieties of proteins e.g., keratin
    Function:
  • strengthen cell and maintain shape
  • stabilize position of other organelles
  • No role in cell movement
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16
Q

What are thick filaments?

A
  • Relatively large (15nm) filaments
  • Composed of myosin protein
  • ONLY in muscle cells
    Function:
  • interact with actin filaments to produce muscle contraction
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17
Q

What are microtubules? (Big)

A
  • Large (25nm), hollow tubes
  • Composed of tubulin protein
    Function:
  • provide cell strength, rigidity; anchor organelles
  • alter shape of the cell, assist in cell movement
  • move vesicles/organelles within cell
  • structural component of centrioles, cilia, and flagella
  • form spindle apparatus for cell division
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18
Q

What are microvilli?

A
  • Short finger-like projections
  • Increase cell surface area (absorption)
  • Contain bundles of microfilaments
  • Attach to cytoskeleton
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19
Q

What are cilia?

A
  • Long slender extensions of cell membrane
  • Composed of microtubules
  • Move fluids across the cell surface
  • Respiratory - reproductive systems
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20
Q

What are centrioles?

A
  • Cylindrical structures
  • 2 per cell
  • Composed of short microtubules
  • Centrosome: centrioles + surrounding cytoplasm
  • Form spindle apparatus during cell division
  • No centrioles  No cell division e.g., muscle cells
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21
Q

What are ribosomes?

A
  • Responsible for protein synthesis
  • Composed of RNA (60%) & protein (40%)
  • 2 subunits: large & small
    Types:
  • free ribosomes scattered in cytoplasm
    • proteins for cell
  • fixed ribosomes attached to ER
    • proteins for secretion
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22
Q

What are proteasomes?

A
  • Contain protein digesting enzymes (proteases)
    Function:
  • break down abnormal/damaged proteins for recycling
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23
Q

What is the endoplasmic reticulum (ER)?

A
  • A network of intracellular membranes
  • Connected to the nuclear envelope
  • Cisternae: storage chambers within membranes
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24
Q

What are the functions of ER?

A
  • Synthesis of proteins, carbohydrates, and lipids
  • Storage of synthesized molecules and materials
  • Transport of materials within the cell
  • Detoxification of drugs or toxins
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25
Q

What is smooth ER?

A
  • No ribosomes attached 
  • Smooth surface
  • Function:
    . synthesis of: phospholipids, cholesterol & steroid hormones
    . synthesis and storage of: triglycerides (liver) & glycogen (liver & muscle)
    . detoxification
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26
Q

What is rough ER?

A
  • Fixed ribosomes attached 
  • Rough beaded surface
  • Function:
    . receives proteins synthesized by fixed ribosomes
    . modify & package proteins
    . transfer proteins via transport vesicles to the Golgi apparatus
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27
Q

What is the golgi apparatus?

A
  • 5-6 flat discs stacked together near the nucleus
    Has 2 faces:
  • forming face (towards RER)
  • maturing face (towards cell membrane)
    Function:
  • modifying, sorting, and packaging macromolecules in vesicles:
    • vesicles enter forming face and exit maturing face
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28
Q

What are the types and functions of the golgi apparatus?

A
  1. Secretory vesicles:
    -modify and package products for exocytosis
  2. Membrane renewal vesicles:
    -renew cell membrane
  3. Lysosomes:
    -carry digestive enzymes to cytosol
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29
Q

What are lysosomes?

A
  • Small spherical vesicles
  • Produced at Golgi apparatus
  • Contain digestive (hydrolytic) enzymes
    2 types/stages:
  • primary lysosomes: contain inactive enzymes
  • secondary lysosomes: contain active enzymes
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30
Q

What is the function of lysosomes?

A
  1. The cell’s garbage disposal system:
    - break down large molecules
    - attack bacteria
    - recycle damaged organelles
    - ejects wastes by exocytosis
  2. Involved in autolysis (self-destruction of damaged or dead cells):
    - lysosome membranes break down
    - digestive enzymes released in cytosol
    - cell proteins and organelles are destroyed
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31
Q

What are lysosomal storage diseases?

A
  • Group of genetic disorders
  • Result from defects in lysosomal function
  • e.g., lipid and glycogen storage diseases
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32
Q

What are peroxisomes?

A
  • Enzyme-containing vesicles (smaller than lysosomes)
  • Enzymes are produced by free ribosomes
  • Break down fatty acids, and organic compounds –> produce H2O2
  • H2O2 –other peroxisomal enzymes–> H2O + O
    -Replicate by division
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33
Q

What are mitochondria?

A
  • Bean-shaped
  • Number depends on cell’s energy demands
    Structure:
  • 2 membranes:
    - smooth outer membrane
    - folded inner membrane (cristae)
    • matrix: fluid around cristae
  • Singular: Mitochondrion
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34
Q

What is the function of mitochondria?

A
  • Fuel stations of the cell
    Energy production:
  • requires O2 and organic substrates
  • generates ATP
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35
Q

What are the processes in energy production?

A
  1. Glycolysis (cytosol):
    - anaerobic
    - glucose –> pyruvic acid
  2. Tricarboxylic acid [Kreb’s] cycle (mitochondria):
    - aerobic (requires O2)
    - pyruvic acid –> CO2
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36
Q

What is the nucleus?

A
  • Largest structure in the cell
  • Headquarter of the cell
  • Single nucleus/cell (exceptions)
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37
Q

What is the outer surface of the nucleus?

A
  1. Nuclear envelope:
    - 2 lipid bilayer membranes around the nucleus
    - between the 2 membranes:
    • perinuclear space
      - outer membrane is:
    • connected to RER
    • covered by ribosomes
  2. Nuclear pores:
    - interruptions of the nuclear envelope
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38
Q

What are the contents of the nucleus?

A
  1. Deoxyribonucleic acid (DNA):
    - all information to build and run organisms
  2. Nucleoplasm:
    - fluid containing ions, enzymes, nucleotides, and some RNA
  3. Nuclear matrix:
    - support filaments
  4. Nucleolus
    - 1 or more per nucleus
    - Composed of RNA, enzymes, and histones
    - Synthesizes rRNA and ribosomal subunits
    - Contributes to protein production
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39
Q

What is the organization of DNA?

A
  1. Nucleosomes:
    - DNA coiled around histones
  2. Chromatin:
    - loosely coiled DNA (cells not dividing)
  3. Chromosomes:
    - tightly coiled DNA (cells dividing)
    - 23 pairs/cell
40
Q

How many chromosomes are there?

A

23, including the sex chromosomes.

41
Q

What is DNA the code for?

A

Instructions for all proteins in the body

42
Q

What is a gene?

A
  • region of DNA
  • instructions for 1 protein
43
Q

What is the structure of DNA?

A
  • Double stranded
  • Structural units: nucleotides
  • Each nucleotide is composed of:
    -deoxyribose (5 C sugar)
    -inorganic phosphate (PO4)
    -1 of 4 nitrogen bases:
    -2 purines: Adenine (A) & Guanine (G)
    -2 pyrimidines: Thymine (T) & Cytosine (C)-
44
Q

What is RNA?

A

3 types:
- messenger RNA (mRNA)
- transfer RNA (tRNA)
- ribosomal RNA (rRNA)

45
Q

What are the differences between RNA and DNA?

A

RNA:
Strands: Single
Sugar: Ribose
Pyrimidine base: Uracil (U)

DNA:
Strands: Double
Sugar: Deoxyribose
Pyrimidine base: Thymine (T)

46
Q

What is protein synthesis? (3 steps)

A
  1. Transcription:
    - copies instructions from DNA to mRNA (in nucleus)
  2. Translation:
    - ribosome reads code from mRNA (in cytoplasm)
    - assembles amino acids into polypeptide chain
  3. Processing:
    - by RER and Golgi apparatus produces protein
47
Q

What is gene activation (mRNA transcription)?

A
  • Uncoils DNA, removes histones
  • Start and stop codes on DNA mark location of gene
  • DNA strands:
    -coding strand: coding for protein
    -template strand: template for mRNA
48
Q

Steps of mRNA transcription?

A

Step 1: gene activation
Step 2: building mRNA
Step 3: RNA editing

49
Q

What is building mRNA (mRNA transcription)?

A

RNA polymerase transcribes DNA:
- binds to start sequence
- reads DNA code for gene
- binds nucleotides to form mRNA
- mRNA duplicates DNA coding strand
- Uracil replaces thymine

50
Q

What is RNA editing (mRNA transcription)?

A

At stop signal, mRNA detaches from DNA:
- code is edited (RNA processing):
-non coding regions (introns) removed
-coding regions (exons) spliced together

51
Q

What are the steps in translation?

A

Step 1:
mRNA moves to a ribosome in cytoplasm
Step 2:
mRNA binds to ribosomal subunits
tRNA delivers amino acids to mRNA
Step 3:
tRNA anticodon binds to mRNA codon
1 mRNA codon translates to 1 amino acid
Step 4:
enzymes join amino acids with peptide bonds
polypeptide chain has specific sequence of amino acids
Step 5:
at stop codon, components separate

52
Q

What is mutation?

A

Change in the nucleotide sequence of a gene
May change gene function  abnormal protein
Causes:
- exposure to chemicals
- exposure to radiation
- mistakes during DNA replication

53
Q

What are the base pairing rules?

A

Apple in the tree
Car in the garage

54
Q

When transporting across the cell membrane, what has to go in and out?

A

Cell membrane is a barrier, but:
nutrients must get in
waste products must get out

55
Q

What are the types of permeability?

A

impermeable: lets nothing in or out

freely permeable: lets anything pass

selectively permeable: restricts movement

56
Q

What is a cell membrane permeability?

A

Cell membrane is selectively permeable:
- allows some materials to move freely
- restricts other materials

57
Q

What factors affect cell membrane permeability?

A

Factors affecting selectivity:
- size
- shape
- electrical charge
- lipid solubility

58
Q

What are the two types of transport through a cell membrane?

A

Passive- no energy required.
Active- requires energy and ATP.

59
Q

What are the three categories of transport?

A

Diffusion (passive)

Carrier-mediated transport (passive or active)

Vesicular transport (active)

60
Q

What is diffusion?

A

Passive transport
Molecules mix randomly
Solute spreads through solvent

60
Q

What is a concentration gradient?

A

Concentration:
- amount of solute in a solvent
Concentration gradient:
- more solute in 1 part of a solvent than another
- solute moves down a concentration gradient
- diffusion eliminates concentration gradient

61
Q

What factors affect diffusion rate?

A
  1. the particle has to move
  2. Molecule size:
    - smaller is faster
  3. Temperature:
    - more heat  faster motion
  4. Concentration gradient:
    - higher gradient  faster diffusion
  5. Electrical forces:
    - opposite charges attract, similar charges repel
62
Q

What is simple diffusion?

A

Materials diffuse through cell membrane:
- lipid-soluble compounds:
- alcohols, fatty acids, and steroids
- lipid-soluble drugs (e.g. halothane)
- dissolved gases:
- oxygen and carbon dioxide

63
Q

What is channel-mediated diffusion?

A

-Channels: transmembrane proteins
-Materials pass through channels:
-water soluble compounds
-Ions
-Factors affecting channel-mediated diffusion:
-size
-electrical charge
-interaction with the channel

64
Q

What is osmosis?

A

-Diffusion of water across the cell membrane
-More solute molecules, lower concentration of water molecules
-Membrane must be:
-freely permeable to water
-not permeable to solutes
-Water molecules diffuse across membrane toward solution with more solutes
-Volume increases on the side with more solutes

65
Q

What are the osmotic and hydrostatic pressures?

A

Osmotic pressure:
- force of a concentration gradient of water
Hydrostatic pressure:
- force needed to block osmosis
Both pressures are:
- opposite in direction
- equal in force

66
Q

What is osmolarity and tonicity?

A

Osmolarity:
- total solute concentration in an aqueous solution
Tonicity:
- (tonos = tension)
- osmotic effect of a solute on a cell
2 fluids may have equal osmolarity, but different tonicity

67
Q

What is a isotonic solution?

A
  • Has equal number of solutes (iso = same)
  • Does not cause osmotic flow of water
    in or out of a cell
    A cell in an isotonic solution:
    • neither gains nor loses water
    • retains shape (biconcave red blood cells)
68
Q

What is a hypotonic solution?

A
  • Has less solutes (hypo = below)
  • Loses water through osmosis
  • A cell in a hypotonic solution:
    • gains water
    • swells –> ruptures (hemolysis of red blood cells)
69
Q

What is a hypertonic solution?

A
  • Has more solutes (hyper = above)
  • Gains water by osmosis
  • A cell in a hypertonic solution:
    • loses water
    • shrinks (crenation of red blood cells)
70
Q

What is carrier-mediated transport?

A

Transport of ions and organic substrates across the cell membrane by binding to integral proteins (carriers)
Characteristics:
- specificity: 1 carrier protein, 1 set of substrates
- saturation limits: rate depends on -transport proteins, not substrate
- regulation: cofactors such as hormones

71
Q

What is cotransport and countertransport?

A
  • Cotransport: = symport
    • 2 substances move in the same direction
  • Countertransport: = antiport
    • 2 substances move in opposite directions
72
Q

What are types of carrier-mediated transport? (3)

A

Facilitated diffusion (passive)

Active transport (active)

Secondary active transport (active)

73
Q

What is facilitated diffusion?

A

Carrier proteins transport molecules too large to fit through channels (e.g., glucose, amino acids):
- molecule binds to receptor site on carrier
- receptor is specific to certain molecules
- carrier changes shape  molecules pass through

74
Q

What is active transport?

A

Requires energy from ATP
Active transport proteins:
- move substrates against concentration gradient
- ion pumps move ions (Na+, K+, Ca+, Mg2+)
- exchange pump countertransports 2 ions at the same time

75
Q

What are sodium-potassium exchange pump?

A

Active transport (countertransport)
Na+-K+ ATPase enzyme moves:
- Na+ out
- K+ in
- 1 ATP moves 3 Na+ & 2 K+

76
Q

What is secondary active transport?

A
  • Na+ concentration gradient drives glucose transport (cotransport)
  • ATP energy pumps Na+ back out
  • Facilitated diffusion –> active transport
77
Q

What is vesicular transport?

A

Active transport
Types:
- endocytosis (endo = into)
- exocytosis (exo = out of)

78
Q

What is endocytosis?

A

A substance gains entry into a cell
3 categories:
- Phagocytosis
- Pinocytosis
- Receptor-mediated endocytosis

79
Q

What is phagocytosis?

A
  • Pseudopodia (psuedo = false, podia = feet) –>
  • Engulf large objects in phagosomes –>
  • Digested by lysosomal enzymes
  • = Cell is eating
80
Q

What is pinocytosis?

A
  • Endosomes “drink” extracellular fluid
  • = Cell is drinking
81
Q

What is receptor-mediated endocytosis?

A
  • Receptors bind ligands
  • Coated vesicle (endosome) carries ligands and receptors into the cell
  • e.g., cholesterol, Fe2+
82
Q

What is exocytosis?

A
  • A substance exits a cell within a vesicle
  • Reverse of endocytosis
83
Q

What is a cell’s life cycle?

A

Most of a cell’s life is spent in a non-dividing state (interphase):
- G-zero phase: cell functions only
- G1 phase: cell growth, organelle duplication, protein synthesis
- S phase: DNA replication and histone synthesis
- G2 phase: finishes protein synthesis and centriole replication

(G=gap - s=synthesis)

84
Q

What are the types of cell division? NO IDEA JUST IGNORE

A

Site
Daughter cells
# chromosomes:
Mitosis- somatic cells
somatic cells 46 (diploid)
Meiosis- sex cells ova or sperms (gametes) 23 (haploid)

85
Q

What are the three stages of mitotic division?

A

DNA replication:
- duplicates genetic material
Mitosis:
- divides genetic material equally
Cytokinesis:
- divides cytoplasm and organelles into 2 daughter cells

86
Q

What is DNA replication?

A

DNA strands unwind
DNA polymerase attaches complementary nucleotides
Result: 2 double stranded DNA:
- each has 1 old strip + 1 new strip

87
Q

What is mitosis?

A

Nuclear division
Divides duplicated DNA into 46 chromosomes
Each chromosome:
- consists of 2 chromatids
- centromere: connects the 2 chromatids
- kinetochore: protein complex around the centromere

88
Q

What are the stages of mitosis?

A

Prophase
Metaphase
Anaphase
Telophase

89
Q

How long is mitosis in minutes?

A

Prophase- 36
Metaphase- 3
Anaphase- 3
Telophase- 18

90
Q

What happens in prophase?

A

Early:
- nucleoli and nuclear envelope disappear
- each centriole moves to a cell pole
- spindle fibers (microtubules) extend between the 2 centrioles
Late:
- spindle fibers attach to kinetochores

91
Q

What is metaphase?

A

Chromosomes align in a central plane (metaphase plate)

92
Q

What is anaphase?

A
  • Microtubules pull chromosomes apart
  • Daughter chromosomes are pulled towards opposite poles near centrioles
93
Q

What is telophase?

A
  • Nuclear envelopes reform
  • Chromosomes uncoil
  • Nucleoli reappear
  • Cell has 2 complete nuclei
94
Q

What is cytokinesis?

A
  • Cytoplasm divides
  • Cleavage furrow around metaphase plate
  • Membrane closes –> two daughter cells
95
Q

What is cell diversity and differentiation?

A

All cells carry complete DNA instructions for all body functions
Cells specialize or differentiate:
- by turning off all genes not needed by that cell

96
Q

How do cell division and tumours relate?

A

Tumor (neoplasm):
- abnormal cell growth and division  cell mass
Types of tumors:
- benign tumor:
- localized
- not life threatening
- malignant tumor:
- Invasive
- may spread  new tumors (metastasis)
- can be fatal
Oncogenes:
- mutated genes that cause tumors

Anatomy and Physiology (13 decks)

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