Cell biology Flashcards

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1
Q

What is stuff made of?

A
  • All ordinary matter in the universe is made of atoms
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2
Q

What are atoms made of?

A
  • protons, neutrons, electrons
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3
Q

What are the simplest atoms?

A
  • hydrogen and helium
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4
Q

How much of the universe is made up of hydrogen and helium?

A
  • more than 99%
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5
Q

When was the big bang?

A
  • 13.7 billion years ago
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6
Q

When did atoms form?

A
  • 380 000 years after the big bang
  • when the universe had cooled enough for electrons to stably associate with protons and neutrons
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7
Q

When did Earth form?

A
  • 4.5 billion years ago
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8
Q

What are the most basic chemical elements?

A
  • the atoms on the periodic table
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9
Q

How do we identity atoms?

A
  • atomic number (number of protons)
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10
Q

How many elements naturally occur on Earth?

A
  • 94
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11
Q

What is a covalent bond?

A
  • sharing of electrons
  • do not break apart in water
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12
Q

What is a molecule?

A
  • two or more atoms connected with covalent bonds
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13
Q

What is a chemical reaction?

A
  • when a molecule is created, broken apart, or modified
  • change in the position of electrons in the molecule
  • change how molecules interact with other molecules
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14
Q

What is an ion?

A
  • atom or molecule has a net electrical charge (positive or negative)
  • missing or extra electron
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15
Q

What is an ionic bond?

A
  • Negatively charged ions can donate an electron to positively charged ions
  • break apart in water
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16
Q

What are salts?

A
  • atoms and molecules connected with ionic bonds
  • dissolve in water
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17
Q

Do water molecules or ionic bonds neutralize electrical charges better?

A
  • water molecules
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18
Q

What are the 6 key chemical elements whose combination make up most of the biological molecules on Earth?

A
  • hydrogen (59%)
  • oxygen (24%)
  • carbon (11%)
  • nitrogen (4%)
  • phosphorus
  • sulfur
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19
Q

What are the 5 main molecules found in cells?

A
  • water
  • sugar
  • fat (lipid)
  • nucleotide
  • amino acid
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20
Q

What are macro-molecules?

A
  • chains of small molecules
  • big molecules
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21
Q

What are carbohydrates made of?

A
  • chains of sugar molecules
  • macro molecules
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22
Q

What do lipid molecules form?

A
  • cell membranes and vesicles
  • macro molecules
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23
Q

What are nucleic acids made of?

A
  • chains of nucleotides
  • RNA and DNA are types of nucleic acids
  • macro molecules
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24
Q

What are proteins made of?

A
  • long chains of amino acids
  • between 100 and 1000 amino acids long
  • macro molecule
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25
Q

What are peptides made of?

A
  • short chains of amino acids
  • macro molecule
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26
Q

What is RNA?

A
  • a ribonucleic acid
  • naturally fold into complex 3-dimensional shapes
  • some can catalyze chemical reactions
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27
Q

What are ribozymes?

A
  • RNA molecules that can catalyze chemical reactions
  • made of RNA
  • can spontaneously interlink nucleotides to form nucleic acids (RNA and DNA) and interlink amino acids to form proteins
28
Q

What are the 2 main problems with ribozymes?

A
  • RNA is fragile. It breaks apart easily
  • RNA is made of 4 different types nucleotides that are not particularly abundant on Earth
29
Q

What are the main catalyst of chemical reactions?

A
  • enzymes
30
Q

What are enzymes?

A
  • Proteins that catalyze chemical reactions
31
Q

What are proteins?

A
  • proteins are what do things in a cell
  • enzymes that catalyze chemical reactions
  • receptors that sense the world around us
  • make up the scaffolding and roads within a cell
  • mediate transport and storage and serve as messengers
32
Q

What is protein synthesis?

A
  • use the strands of RNA floating around as instructions for how to put amino acids together (in what order) to form useful proteins
33
Q

What do cells need to synthesize a protein?

A
  • 2 types of RNA (mRNA and tRNA)
  • a bunch of free amino acids
34
Q

What is mRNA?

A
  • a long, unfolded strand of RNA, which represents the instructions
35
Q

What is tRNA?

A
  • a bunch of short, folded up pieces of RNA, which read the instructions
  • about 76 nucleotides long
  • On one end, there are 3 exposed nucleotides that can bind a complementary 3-nucleotide sequence of mRNA
  • On the other side, there is pocket that is highly attractive to a free-floating amino acid
  • there are unique tRNA molecules to carry each type of amino acid
36
Q

How many types of amino acids are there?

A
  • 20
37
Q

How do cells make proteins?

A
  • encouraging tRNA molecules to find a sequence of mRNA that they complement
  • a chemical reaction is needed to interlink the amino acids that are held by the tRNA molecules
  • based on the sequence of the genetic code (mRNA), 20 types of amino acids get strung together in different combinations to form all the proteins of life
38
Q

What is a ribosome?

A
  • the first organelle
  • a molecular machine that is made of RNA and proteins
  • perfected the synthesis of new proteins by stringing together the amino acids held by tRNA molecules in the order determined by free-floating strands of mRNA

interlink amino acids in the order dictated by the genetic code.
synthesize proteins by translating the RNA that was transcribed from DNA.

39
Q

How do ribosomes work?

A
  • The small subunit of the ribosome grabs a free-floating strand of mRNA
  • the large subunit of the ribosome identifies free floating tRNA molecules that complement the section of mRNA held by the small subunit
  • Ribosomes slide across mRNA, taking one step each time they find a tRNA molecule that complements the mRNA segment held by the small subunit
  • When a ribosome finds an appropriate (complementary) tRNA molecule, it removes its amino acid and attaches it to the amino acid of the next complementary tRNA molecule
  • Step by step, the ribosome links together amino acids held by tRNA molecules based on the sequence of nucleotides in free-floating strands of mRNA

Ribosomes synthesize new proteins by translating strands of mRNA, interlinking the amino acids held by tRNA molecules in the order determined by the genetic code.

40
Q

What do cells use for long term information storage?

A
  • DNA (more stable and durable than RNA)
41
Q

How does DNA synthesize protein?

A
  • All the instructions of life are stored in strands of DNA
  • Sections of DNA are transcribed into mRNA
  • mRNA is translated into proteins
  • Protein enzymes catalyze the chemical reactions of life
42
Q

What are phospholipids?

A
  • strands of lipids with a phosphate cap
  • Lipids prefer the company of other lipids
  • Phosphate caps prefer to interact with water
  • phospholipids form bilayer sheets if left undisturbed (in water)
43
Q

What are micelles?

A
  • soap bubbles
  • formed when phospholipids are shaken
  • under right conditions, can pop and reform as liposomes
44
Q

What is the cell membrane?

A
  • basically a liposome
  • Diffusion through the phospholipid bilayer is limited
  • Inside and outside are salt water
45
Q

What are prokaryotic cells?

A
  • the first cells
  • consist of a cell membrane filled with cytoplasm
  • in cytoplasm, loose strands of DNA and RNA, and ribosomes
46
Q

What is cytoplasm?

A
  • water filled with salt, sugar, nucleic acids, and amino acids
47
Q

What are eukaryotic cells?

A
  • similar to prokaryotic
  • have mitochondria
  • nucleus and chromosomes
48
Q

What is the mitochondria?

A
  • molecular machines that extract energy from nutrients
  • generate molecules of ATP, cell’s main source of chemical energy, by digesting molecules of sugar
49
Q

What is a chromosome?

A
  • compacted strand of DNA in a nucleus
  • not allowed to leave the nucleus
50
Q

What is a genome?

A
  • The genome of a cell refers to its entire collection of DNA
  • provides the information necessary to synthesize all the cell’s proteins
51
Q

What are genes?

A
  • sections of the genome that get transcribed into RNA and translated into protein
  • section of DNA that codes for a specific protein
  • Most genes are only expressed by some cells some of the time
52
Q

What happens when a gene is read?

A
  • that segment of DNA is transcribed into RNA in the nucleus
  • RNA is allowed to leave the nucleus, so it can meet up with a ribosome to be translated into a protein
53
Q

How many genes do humans have in their genome?

A
  • 20 000 protein encoding genes
  • make up less than 2% of human genome
54
Q

What is the cell body?

A
  • SOMA
  • where the cell’s nucleus is located
  • neurons are defines by where their soma is
  • made up of cytoplasm, mitochondria, microtubules
55
Q

What is the cell membrane?

A
  • defines the boundary of the cell
  • consists of a phospholipid bilayer that is embedded with proteins
56
Q

What are microtubules?

A
  • allow for rapid transport of material within the neuron
57
Q

What are multicellular organisms?

A
  • all complex multicellular organisms are exclusively eukaryotic
  • collections of cells stuck together (consist of more than one cell)
  • cells specialize to perform distinct functions
  • all cells have the same genome, but they read different parts of it
58
Q

What person do you think advanced the field of neuroscience the most?

A
  • Charles Darwin
  • The theory of evolution suggested that we could learn a lot about the human brain by studying the brains of other animals
59
Q

Who do humans share 98.8% of their DNA with?

A
  • chimpanzees
  • human genome is very similar to the genomes of the other great apes
60
Q

What is the difference between humans and great apes?

A
  • humans have much bigger brains and way more neurons
  • neuron number generally correlates with cognitive complexity, but not always
61
Q

Which mammalian species are closer to humans?

A
  • rodents
  • rodents have become the dominant species used in neuroscience research
62
Q

Why do we use rodents in research?

A
  • mammalian/rodent brain structure is highly similar to human brain structure
63
Q

How are rodents like us?

A
  • have complex decision-making abilities
  • get stressed out, depressed, and anxious
64
Q

What do we study in rodents?

A
  • neural mechanisms of sensory, motor, and cognitive processes, including motivations, emotions, learning and memory, and decision-making
  • model human diseases in rodents to figure out how best to treat these conditions in humans
65
Q

How are human brains unique?

A
  • develop very slowly
  • brain and behaviour plastic (malleable, shapeable) far longer than other animals
  • human brain grows (in weight)
  • stops making new neurons halfway through its gestation in the womb
  • growth of existing neurons, which continue to establish new connections with other neurons throughout life
  • increases in the number of other cells in the brain (the support staff), which continue to replicate throughout the lifespan
66
Q

What is neoteny?

A
  • prolongation of maturation
  • extended youth
67
Q

What is the Fermi paradox?

A
  • 40 billion earth-like planets that could support life
  • some of its earth-like planets are likely way older than planet Earth
  • we estimate a life-form could colonize the entire Milky Way galaxy in less than 50 million years
  • 2 trillion other galaxies
  • So…why haven’t we seen any aliens? Where is everybody? Could it really be just us?
  • assume there’s a unique condition on Earth or the first complex cell was uniquely special