Cell Structure and Function Flashcards

1
Q

Organismal functions depends on what.

A
  • individual and collective cell functions

- if one breaks down, we see disease/dysfunction

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2
Q

What do epithelial cells do?

A
  • connect body parts
  • form linings
  • transport gases
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3
Q

What do smooth/skeletal cells do?

A

move things

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4
Q

What do fat cells do?

A

store nutrients

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5
Q

What do macrophages do?

A

fight disease/body invaders

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6
Q

What do sperm cells do?

A

reproduce

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7
Q

What do nerve cells do?

A

gather information and control body functions

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8
Q

Describe the plasma membrane.

A
  • barrier between cell and external environment

- can pass ions through membrane but it depends on what it is

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9
Q

Fluid inside the cell is called?

A

intercellular fluid (ICF)

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10
Q

Fluid outside the cell is called?

A

extracellular fluid (ECF)

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11
Q

Describe the nucleus.

A
  • info centre
  • DNA inside of here
  • transcribes info for all proteins that body needs
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12
Q

What is the cytosol?

A

watery environment including organelles

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13
Q

What does the cytoplasm consist of?

A
  • cytosol

- organelles

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14
Q

What model describes the structure of the plasma membrane, and what does it consist of?

A
  • fluid mosaic model
  • phospholipid bilayer
  • cholesterol
  • membrane proteins
  • membrane carbohydrates
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15
Q

Describe phospholipids.

A
  • basic structure of the membrane
  • barrier to passage of substances between ICF and ECF
  • provides fluidity to the membrane
  • impermeable to water
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16
Q

What are aquaporins?

A
  • integral membrane proteins

- pores that allow water to travel through

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17
Q

Phosphate heads are ______ & _____, while fatty acid tails are ______ & _____.

A
  • polar & hydrophilic

- non polar & and hydrophobic

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18
Q

What does cholesterol do?

A
  • adds fluidity to the cell membrane
  • interferes with hydrophobic interactions between phospholipids
  • decreases permeability of membrane to water
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19
Q

membrane lipids are made up of 75% ______ (____ ____), 5% ______ & ______, and 20% _______.

A
  • phospholipids (lipid bilayer)
  • glycolipids & glycoproteins
  • cholesterol
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20
Q

What does glycolipids & glycoproteins consist of?

A

outer membrane surface

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21
Q

Describe integral membrane proteins.

A
  • amphipathic
  • some proteins are transmembrane proteins (i.e. channels)
  • some are located on one side of the membrane (enzymes, receptors)
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22
Q

Describe peripheral membrane proteins.

A
  • easily dissociated from the cell membrane
  • most located on cytosolic side of the membrane
  • membrane carbohydrates bound to membrane proteins (extracellular side)
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23
Q

What are the functions of membrane carbohydrates bound to membrane proteins?

A
  • glycocalyx: appears as a brush holder, holds cell together/protection
  • antigens: cell recognition
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24
Q

What are the 3 general cell functions?

A
  • metabolism
  • cellular transport
  • intercellular communication
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25
List the steps of metabolism.
- anabolism - synthesis - catabolism - breakdown
26
metabolism =
chemical reactions in body
27
Describe the steps of cellular transport.
- non polar molecules diffuse across the phospholipid bilayer - polar molecules go through mediated transport with protein carriers and move through ion channels - vesicular transport
28
What does intercellular communication do?
coordinate cell activity for homeostasis
29
What does direct intercellular communication use? Give examples.
- gap junctions | - ex. cAMP, Ca 2+
30
What does indirect intercellular communication use? Give examples.
- messengers and receptors - chemical messengers released by one cell to act on specific receptors on another cell - ex. insulin and GLUT 4 receptors (insulin released by pancreatic b cells acts on insulin receptors in most cells to facilitate glucose uptake
31
What are the 2 categories of cell-to-cell adhesions?
- membrane junctions | - specialized junctions
32
What are the 3 components of specialized junctions?
- tight junctions - desmosomes - gap junctions
33
Describe membrane junctions: tight junctions.
- prevents fluids and most molecules from moving between cells - preventing foreign bodies (bacteria etc.) - providing a barrier to cancer cells
34
Describe desmosomes.
- binds cells together for strength ("spot welds") | - found in tissue subject to mechanical stress (ex. uterus, stomach, bladder)
35
Describe gap junctions and give an example.
- composed of membrane proteins - link the cytosol of 2 adjacent cells - form pores so that ions and molecules can moved between cells, act as a signal - ex. direct communication: electrical sign in cardiac muscle
36
What is the function of the nuclear envelope?
forms the membrane of the nucleus
37
What is the function of nuclear pores?
selective movement of materials through the nuclear envelope
38
What happens at the nucleolus?
site of ribosomal RNA (rRNA) synthesis
39
Name 3 functions of the nucleus.
- trasmission and expression of genetic information - contains DNA: stores the genetic code - DNA transcribed to RNA: necessary to express the genetic code
40
The cytoplasm is composed of _______ + _______.
cytosol (fluid of cell) + organelles
41
Name 3 functions of cytosol.
- location of specific chemical reactions - storage of fat and carbohydrates - storage of secretory vesicles
42
What are the 2 categories of organelles?
- membranous organelles | - non-membranous organelles
43
What are the 5 membranous organelles?
- Endoplasmic Reticulum (ER) - golgi apparatus - mitochondria - lysosomes - peroxisomes
44
What are the 4 non-membranous organelles?
- ribosomes - vaults - centrioles - cytoskeleton
45
What are the 2 categories of the endoplasmic reticulum (ER)?
- rough ER | - smooth ER
46
Describe the rough ER.
- flattened sacs | - granular appearance due to ribosomes
47
Describe the smooth ER.
- tubules | - smooth appearance
48
What is the function of the ER?
protein and lipid synthesis for use by organelles or other cells
49
What is the function of the golgi apparatus?
processing and packaging of proteins, then directed to target
50
What are the functions of the mitochondria?
- powerhouse of the cell - mass ATP producer - CHO, fat, or protein derivative - O2 utilization
51
What are the functions of the lysosomes?
- enzymatic process | - contain enzymes that degrade cellular or extracellular debris
52
Name and describe the 2 processes that happen with lysosomes.
- endocytosis: extracellular, vesicle formation and lysosome degradation - phagocytosis: intracellular, engulfs particles
53
What is the function of peroxisomes?
degrade waste molecules i.e. amino acids, fatty acids, and toxic foreign substances
54
What is the by product of the process completed by peroxisomes?
- H2O2 (hydrogen peroxide) - forms water and oxygen through enzymatic conversion - reaction is immediate
55
Ribosomes = _____ and ______.
rNA and proteins
56
What is the function of ribosomes?
integral for protein synthesis
57
What are the 2 types of ribosomes? Describe each.
- fixed: attached to rough ER | - free: loose in cytosol
58
What are vaults? What are its functions?
- barrel-shaped - recently discovered - transport of molecules within the cell - function largely unknown
59
Why could vaults possibly become part of cancer treatment?
linked to apoptosis (programmed cell death)
60
What are centrioles? What are its functions?
- paired cylindrical structures - perpendicular to each other - function in cell division - develop spindle fibres - organize
61
What is the cytoskeleton?
- lattice of fibrous proteins (framework, basic foundation) | - keeps organelles in place
62
What are the functions of the cytoskeleton?
- support and structure - transport of materials - suspension of organelles - formation of adhesions with other cells - contraction
63
Each​ ​of​ ​the​ ​parts​ ​of​ ​cytoskeleton​ ​differ​ ​in​ ​size. What are these?​ ​(how are​ ​they​ ​are​ ​classified?)
- Microfilament - ​Intermediate​ ​filament - ​Microtubule
64
Name the 4 general steps of protein synthesis.
- code for proteins (genetic code) - DNA is transcribed in the nucleus to mRNA - mRNA moves from the nucleus to the cytoplasm - mRNA is translated by ribosomes to proteins
65
Define gene.
a portion of DNA holding the genetic code
66
Define triplet.
a nucleotide sequence that codes for a specific amino acid
67
What happens when the genetic code is being transcribed?
- DNA is transcribed to mRNA | - a triplet is transcribed into a codon
68
What is transcription?
process where RNA is synthesized using DNA
69
What are the 3 types of RNA?
- mRNA: messenger - rRNA: ribosomal - tRNA: transfer
70
What is the function of RNA polymerase?
- enzyme - binds to a sequence of DNA - DNA uncoils - mRNA forms behind it - catalyzes the formation of bonds between nucleotides of mRNA
71
Describe the process of translation.
- requires mRNA, tRNA, and rRNA (rRNA is within the ribosome) - occurs in the cytoplasm - translate info to form the polypeptide sequence
72
How is the destination of proteins determined?
- determined by leader sequence (synthesized 1st) - boss - requires free ribosomes in cytosol - what to do, where to go (in cell, out of cell)
73
What is post translational processing?
- takes polypeptide and processes it into the final product - in terms of the cell, remove leader sequence-job is done, polypeptide is at its destination - cleavage of excess amino acids
74
What are the 2 additions at post translational processing?
- lipids | - carbohydrates
75
Describe the packaging of proteins.
- from the ER (processing) | - to the golgi apparatus (close association with ER, packaged into vesicles)
76
Describe cell division.
- most cells have a limited life span | - mitosis replaces cells
77
What is a chromosome?
- one complete DNA molecule plus associated proteins | - chromosomes are coiled around histones
78
Humans have __ pairs of chromosomes. One ______ set and one ______ set.
- 23 pairs - parental set - maternal set
79
Define chromatin.
threads of DNA within the nucleus
80
Define chromatid.
individual component of chromosome pairs
81
Define centromere.
center portion that links chromatids
82
Define centrioles.
- organelle - forms spindle fibres - associated with organization of cell components
83
Name the 7 events in the cell cycle.
- interphase - prophase - prometaphase - metaphase - anaphase - telophase - cytokinesis
84
Describe interphase.
normal functions of cell
85
Describe prophase.
- chromatin pairs condense - mitotic spindle forms (from microtubules) - centriole pairs move to opposite ends of cell
86
Describe prometaphase.
- nuclear envelope breaks down - no nucleolus - chromosomes linked to spindle fibres
87
Describe metaphase.
chromosomes aligned at the middle of the cell
88
Describe anaphase.
- chromatid pairs separate - chromosomes move along mitotic spindle to opposite poles - cytosol starts to take place
89
Describe telophase.
- new nuclear envelopes - chromosomes de-condence (to chromatin) - mitotic spindle starts breaking down
90
Describe cytokinesis.
division of the cytoplasm (starts to occur in anaphase or telophase)