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HEAL1500 > UNIT 2 - CELL STRUCTURE AND FUNCTION > Flashcards

UNIT 2 - CELL STRUCTURE AND FUNCTION Flashcards

1
Q

what is a cell?

A

-the basic unit of life

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2
Q

how do new cells arise?

A

-from preexisting cells

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3
Q

what is common among all living organisms?

A

-organized
-acquire materials + energy
-homeostatic
-respond to stimuli
-reproduce and have potential for growth
-evolutionary history

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4
Q

why are cells small?

A

-to maintain a high SA-V ratio
-large amount of SA in comparison to volume
-critical to survival

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5
Q

why is it important for cells to have a larger surface area in comparison to their volume? are there limits to this?

A

-allows for more nutrients and wastes to be cycles in/out of the cell
-a cell can get too large and not be efficient/metabolically active

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6
Q

what are the two categories of cells?

A

-prokaryotes + eukaryotes

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7
Q

what are distinct features of prokaryotic cells?

A

-lack a nucleus
-have 2 groups of bacteria (archaebacteria and eubacteria)

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8
Q

what are distinct features of eukaryotic cells?

A

-have a nucleus
-includes animals, plants, fungi, and protists

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9
Q

what do both eukaryotes and prokaryotes have?

A

-plasma membrane
-cytoplasm

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10
Q

what is the plasma membrane made of? what is its purpose?

A

-phospholipid bilayer
-contains proteins attached + embedded
-to separate the cells internal and external environments

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11
Q

what is special about the phospholipid bilayer?

A

-selectively permeable (controls what comes in and out)

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12
Q

what is the cytoplasm?

A

-semifluid substance inside the cell
-includes organelles

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13
Q

what were the first cells on earth? what evolved from these cells? what was specific about the atmosphere at this time?

A

-prokaryotes (archaeans)
-eukaryotes evolved
-it contained no oxygen

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14
Q

do archaeans survive today?

A

-in very inhospitable conditions (acid, hot, salt aka thermal vents)

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15
Q

how do we predict organelles developed in the eukaryotic cells? what is this idea called?

A

-eukaryotes engulfing prokaryotic cells
-endosymbiosis

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16
Q

how did cells gain a nucleus?

A

-from invagination of the plasma membrane
-eventually surrounding dna with a double membrane

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17
Q

how did the endomembrane system come about?

A

-proliferation of membranes (rapid growth of new parts of the membrane)

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18
Q

how did the cell gain mitochondria and chloroplast organelles?

A

-engulfing aerobic and photosynthetic bacteria (prokaryotes)

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19
Q

how does the behaviour of phospholipids cause the plasma membrane to form?

A

-when placed in water, they will naturally form a spherical bilayer
-hydrophilic heads = towards cytoplasm + extracellular fluid
-hydrophobic tails inward

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20
Q

what is the model used to describe the plasma membrane? why is it described this way?

A

-fluid mosaic model
-elements such as proteins are able to move freely laterally in the membrane

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21
Q

what helps support the plasma membrane?

A

-cholesterol

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22
Q

what 2 molecules act as receptors to identify cells as foreign or self? what kind of function is this?

A

-glycoproteins
-glycolipids
-immune

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23
Q

what makes glycoproteins and glycolipids/

A

-attached carbohydrate chains

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24
Q

what substances/molecules are able to pass freely through the plasma membrane? what are some examples?

A

-small hydrophobic substances
-ex: gases (oxygen, carbon dioxide, estradiol)

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25
what substances/molecules need help passing the plasma membrane? what are examples?
-ions and larger molecules -ex: water, Na+, K+
26
what is the membrane channel protein that allows water to pass through?
-aquaporin
27
what is simple diffusion?
-the random movement of molecules from a high to low concentration -passive movement (no energy)
28
when does simple diffusion occur until?
-until molecules are equally distributed -equal #s of molecules moving in and out of the cell
29
what is to be said about the movement of molecules in simple diffusion?
-move in both directions -net movement is from high to low concentration
30
what is osmosis?
-the diffusion of water molecules from high to low water concentration -passive movement (no energy)
31
what does it mean for a solution to be isotonic? how do cells react when placed in an isotonic solution (body fluid)?
-same concentration of impermeable solutes in comparison to a body fluid or cell -cells do not change size (no net movement)
32
what does it mean for a solution to be hypotonic? how do cells react when placed in a hypotonic solution?
-solution with fewer solutes -cells will swell and burst (more water movement into the cell)what
33
what is a cell swelling + bursting also referred to as?
-lysis (membrane breaking down)
34
what does it mean for a solution to be hypertonic? how do cells react when placed in a hypertonic solution?
-solution with more solutes -cells will shrink (water movement out of the cell)
35
what is a cell shrinking also referred to as?
-crenation
36
what drives osmosis?
-osmotic pressure
37
what is facilitated transport?
-transport of molecules from a high to low concentration via a protein carrier -passive movement (no energy) -protein transporters are specific and only move certain molecules
38
what are the 2 main transport proteins?
-channels ( gated or ungated) -uniporter carriers (open one side, close, then open other side)
39
what is active transport?
-movement of molecules from low to high concentration
40
what is primary active transport?
-a pump using ATP as energy -uniport (one molecule) -cotransport (2 different molecules going different ways)
41
what is secondary active transport?
-energy is provided by one molecules gradient and another molecule is moved using that energy -symport (2 molecules move in the same direction) -antiport (2 molecules move in opposite directions)
42
what is bulk transport?
-movement of large molecules across the membrane using endocytosis or exocytosis methods
43
what is endocytosis? what are the 3 methods that are used?
-transports molecules or cells into the cell via invagination of the plasma membrane to form a vesicle -phagocytosis -pinocytosis -receptor-mediated endocytosis
44
what is phagocytosis?
-endocytosis of pathogens (bacteria) -done by white blood cells
45
what is pinocytosis?
-endocytosis of fluid with small particles (solutes) -microvilli of small intestine
46
what is receptor-mediated endocytosis?
-particles must bind to receptors in the plasma membrane to initiate endocytosis -receptors cluster to form coated pits -brings in useful substances (typically)
47
what is exocytosis?
-transports molecules outside the cell via the fusion of a vesicle with the plasma membrane -reverse endocytosis
48
what is the nucleus?
-contains genetic instruction for making proteins involved in cell function -contains DNA in chromatin form typically
49
do all cells contain the same genes?
-YES
50
what is the nucleoplasm?
-fluid inside the nucleus
51
what is the nucleolus?
-dark region inside the nucleus -produces ribosomal RNA (rRNA)
52
what is the nuclear envelope?
-a double membrane (phospholipid bilayer) around the nucleus
53
what are the nuclear pores?
-holes in the nuclear envelope -allow substances to pass in + out
54
what is the endomembrane system?
-series of membranous organelles that function to process and transport materials for the cell -also for compartmentalization
55
what are ribosomes?
-made of rRNA and protein -sites of protein synthesis -attached to the outer nuclear membrane and the rough endoplasmic reticulum or free floating the cytoplasm
56
what are groups of free floating ribosomes called?
-polyribosomes
57
what organelles make up the endomembrane system?
-nuclear envelope, endoplasmic reticulum, golgi apparatus, lysosomes, and vesicles
58
what is the rough endoplasmic reticulum?
-folded membrane studded with ribosomes -proteins made here go to nearly all areas of the cell
59
where do the proteins made by the free floating ribosomes go?
-cytosol -mitochondria -nucleus
60
what is the smooth endoplasmic reticulum?
-folded membrane that lacks ribosomes -synthesizes lipids
61
what is the golgi apparatus?
-flattened membrane sacs -modify proteins and lipids -help in processing, packaging, and secreting
62
what are vesicles?
-small membranous sacs (phospholipid bilayer) used for transport -break off from ER or golgi apparatus
63
what are lyososomes?
-vesicles containing hydrolytic enzymes that break off from the golgi apparatus -break down molecules into smaller parts -common in white blood cells (engulf disease causing microbes)
64
what is the cytoskeleton?
-protein fibers that help maintain cell shape + anchor and/or move organelles in the cell -3 fibers
65
what are the 3 fibers that make up the cytoskeleton?
-microtubules -intermediate filaments -actin filaments
66
what are the characteristics/functions of microtubules?
-maintain cell shape -largest fiber of the cytoskeleton -help organelles move (act as tracks) -assembly controlled by the centrosome -forms spindle apparatus during cell division to help move chromosomes -dynamic structure (elongates + shortens)
67
what are the characteristics/functions of intermediate filaments?
-internal structure + cohesion (anchoring) of cells (strength) -consist of keratin or vimentin proteins
68
what are the characteristics/functions of actin filaments?
-cell movement (flagella + muscle) -smallest fiber of the cytoskeleton -long and very thin -made of actin protein
69
what is characteristic of flagella and cilia? where can we see each?
-both contain microtubules -both are used in movement -cilia : respiratory tract to move mucus -flagella : sperm cells to propel to the egg
70
what is the extracellular matrix?
-protective mesh of proteins and polysaccharides -surrounds the cell that produces it
71
what is contained within the extracellular matrix?
-collagen (resists stretching) -elastin (resilience/elasticity) -fibronectin (adhesive protein) binds to integrin (integral membrane protein) connected to the cytoskeleton (role in cell signalling)
72
what are the types of cell junctions?
-adhesion junctions -tight junctions -gap junctions -desmosomes -nanotubes
73
what are adhesion junctions?
-attach cytoskeletons of adjacent cells (velcro belt) -attach actin filaments
74
what are tight junctions?
-waterproof barrier
75
what are gap junctions?
-fuse of 2 channels (create clusters of joined channels) -allows for communication between cells
76
what are desmosomes?
-strong disk like junctions joining 2 cells cytoskeletons -attach intermediate filaments
77
what are nanotubes?
-actin containing protrusions that connect cells -can form tunnels to transfer signals and various things (proteins, soluble molecules, and organelles (mitochondria))
78
what is special about the mitochondrion membrane?
-has an inner and outer membrane surrounding the matrix (space between) -inner membrane is folded into cristae which contain enzymes for cellular respiration
79
what is the main function of the mitochondrion?
-convert chemical energy from glucose into ATP
80
what does cellular respiration use up? what does it give off?
-uses up oxygen -gives off carbon dioxide
81
do mitochondria have their own DNA?
-YES -mitochondrial DNA (some for proteins, tRNA, and rRNA) -meaning they can multiply
82
what is the basic idea of what cellular respiration does?
-breaks down glucose into carbon dioxide and water
83
what are the 4 main steps of cellular respiration?
-glycolysis -intermediate reaction -citric acid cycle (Krebs cycle) -electron transport chain
84
why do we say that 30 ATP are made per glucose molecule when 32 are actually produced/
-2 ATP are used to bring 2 NADH from glycolysis into the mitochondria
85
is NAD+ the oxidized or reduced form?
-oxidized -oxidation is loss of electrons
86
is NADH the oxidized or reduced form?
-reduced -reduction is gain of electrons
87
does NADH OR NAD+ act as the electron transporter?
-NADH
88
what are the basics of glycolysis?
-breaks glucose into 2 pyruvates -occurs in the cytoplasm -anaerobic (does not need oxygen) -produces 2 NADH and 2 ATP molecules
89
what happens in the first half of glycolysis?
-2 ATP molecules are needed to phosphorylate glucose
90
what happens in the second half of glycolysis?
-phosphorylation occurs without the need of ATP -2 NADH, 4 ATP, and 2 pyruvates are formed
91
what is the intermediate reaction?
-occurs when oxygen is available -occurs in the mitochondria -produces 2 NADH and 2 CO2 per glucose (1/2 per pyruvate) -prepares pyruvates for the Krebs cycle -pyruvates become acetyl CoA
92
what is the citric acid cycle?
-series of enzymatic reactions -occurs in the matrix of the mitochondria -completes the breakdown of glucose (breaks carbon bonds) -produces 6 NADH, 2 FADH2, and 2 ATP per glucose (1/2 per acetyl CoA) -releases 4 CO2
93
what carries hydrogen and electrons away in the citric acid cycle? where are the electrons taken?
-NADH -FADH2 -electron transport chain
94
what can be converted into compounds that can enter the citric acid cycle?
-fats -proteins
95
what makes up the electron transport chain?
-carrier protein complexes embedded in the mitochondrion's cristae
96
what occurs along the electron transport chain?
-each carrier accepts 2 electrons and passes them along -H+ ions get transferred between the inner and outer mitochondria membrane (more from NADH, less from FADH2) -oxygen is the final acceptor
97
is the electron chain anaerobic or aerobic?
-aerobic (needs oxygen)
98
what happens once the oxygen accepts the electron?
-combines with hydrogen atoms to become water
99
how does our breathing relate to cellular respiration?
-we breath in oxygen to be used as the electron acceptor
100
what are the total net products of cellular respiration?
-30 ATP -10 NADH -2 FADH
101
what is fermentation?
-occurs when oxygen is not available (anaerobic) -glycolysis still occurs -produces lactate (toxic) instead of acetyl CoA -cori cycle gets rid of lactate -2 ATP produced per glucose

HEAL1500 (12 decks)

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