BIOL1001 > Midterm #1 > Flashcards

Midterm #1 Flashcards

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1
Q

What are the 7 properties of living organisms?

A
  1. Have structure/order
  2. Require energy/metabolize
  3. Develop and grow (gain mass, change form)
  4. Respond to stimuli (environmental sensitivity)
  5. Regulate
  6. Reproduce
  7. Adapt (evolutionarily speaking)
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2
Q

What is evolution?

A

The concept that organisms today are adapted descendants of our ancestors - also how organisms change over time and respond to their environment.

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3
Q

What is the scientific method (8 steps)?

A
  1. Ask a question about an observation
  2. Do background research
  3. Construct a falsifiable hypothesis
  4. Set your predictions
  5. Construct an experiment to test your explanation
  6. Collect data
  7. Analyze data
  8. Support or refute hypothesis (refine hypothesis)
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4
Q

What is the difference between an independent and dependent variable?

A

DRY - dependent, responsive, Y
MIX - manipulated, independent, X

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5
Q

Describe the hierarchy of biological organization starting with the molecule.

A

Molecule, organelle, cell, tissue, organ, body system, organism, population, community, ecosystem, biosphere.

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6
Q

What is taxonomy?

A

The biological branch of naming and classifying.

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7
Q

What is the order of classification in the Linnean Classification system?

A

Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

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8
Q

How are the three domains differentiated?

A

Domain Bacteria and Domain Archaea contain prokaryotes.
Domain Eukarya contains eukaryotes.

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9
Q

What is the difference between prokaryotic and eukaryotic cells?

A

Prokaryotic cells:
- small (in comparison to eukaryotes)
- no nucleus
- no membrane-bound organelles
- most have cell wall or capsule

Eukaryotic cells:
- large (in comparison to prokaryotes)
- double membrane bound nucleus that contain DNA as chromosomes
- contain membrane bound organelles

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10
Q

How are the 4-ish kingdoms in Eukarya organized?

A
  • Kingdom Plantae: multicellular autotrophs
  • Kingdom Animalia: multicellular, ingest other organisms (heterotrophic)
  • Kingdom Fungi: uni/multicellular eukaryotes that are heterotrophic
  • Protists: generally unicellular, diverse
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11
Q

Identify the differences between a phylogenetic tree and a cladogram.

A

Phylogenetic tree:
- A branching diagram that represents a hypothesis about the evolutionary history of a group of organisms
- Represents evolutionary time and genetic distance between organisms
- Based on morphological characteristics + also genetic relationships

Cladogram:
- Simpler diagram showing the evolutionary history of organisms without representing evolutionary time/amount of change
- Does not represent evolutionary time and genetic distance between organisms
- Based on morphological characteristics alone

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12
Q

What are the chemical and physical processes of life arising? (4 steps)

A
  1. Abiotic synthesis of small organic molecules
  2. Joining of these small molecules into macromolecules
  3. Packaging of molecules into protocells
  4. Origin of self-replicating molecules
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13
Q

What are the four hypotheses for the synthesis of organic molecules?

A

Hyp. 1: Earth’s early atmosphere was a reducing environment in which organic compounds could have formed from simpler molecules (Oparin-Haldance hypothesis)
Hyp. 2: Earth’s early atmosophere was neutral, but organic compounds formed in reducing environments close to volcano openings
Hyp. 3: Organic compounds were first produced in deep sea hydrothermal vents
Hyp. 4: Organic compounds came from meteorites

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14
Q

What is a protocell?

A

An abiotic precursor of a living cell that had a membrane-like structure and that maintained an internal chemistry different to that of its surroundings (referred to as a vesicle)

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15
Q

What is the oxygen revolution that occurred after the first cyanobacteria formed?

A

Oxygen (photosynthesis byproduct of blue-green algae/cyanobacteria) saturated the water and began to fill the atmosphere - this is the “oxygen revolution”

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16
Q

What is a niche?

A
  • The specific environmental and ecological conditions that are available for life to use
  • Often described within the context of an n- dimensional hyperspace
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17
Q

What is endosymbiotic theory and what is the supporting evidence for it? (6 facts) (Lynn Margulis work)

A
  • An evolutionary theory of the origin of eukaryotic cells from prokaryotic cells
  • Mitochondria and chloroplasts originated as prokayotic cells engulfed by an ancestral eukaryotic cell - the engulfed cell and its host cell (aka endosymbiont) evolved into a single organism. The prokaryotic cell may have gained entry as undigested prey or as an internal parasite, but eventually benefitted the host

6 facts that support origin of mitochondria and chloroplasts:
1. Their inner membranes are very similar to plasma membranes of prokaryotes
2. Their enzymes and transport systems are very similar to prokaryotes
3. They replicate by a splitting process that is similar to some prokaryotes
4. They contain circular DNA not associated with histones, like prokaryotes
5. They have the cellular machinery needed to transcribe and translate their own DNA into proteins
6. Their ribosomes, in the organelles, are more similar to prokaryotic ribosomes than they are to the cytoplasmic ribosomes of eukaryotic cells.

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18
Q

What and when did the Cambrian Explosion occur?

A
  • 541-530 mya
  • Rapid diversification
  • Most modern animal phyla emerged at this time
  • Oxygen level in the atmosphere hit a concentration where large complex life could be sustained
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19
Q

What is cell theory?

A

All living things are made of cells
(all cells come from pre-existing cells, basic unit of life)

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20
Q

What is unity?

A

Two species sharing certain traits because of a common ancestor

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21
Q

What is diversity?

A

Two species differ because certain heritable changes occur after the two species diverged from the common ancestor.

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22
Q

What is a hypothesis?

A
  • A tentative answer to a well framed question that arises from observations
  • Must be falsifiable
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23
Q

What is a prediction?

A
  • An expected outcome if the proposed explanation is true
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24
Q

What is a theory?

A

An explanation that is broader in scope than a hypothesis, generates new hypotheses, and is supported by a wide body of evidence.

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25
What is the control group?
No treatment, all other variables remain consistent.
26
What is the experimental group?
The group that receives the treatment
27
What is inductive reasoning?
Drawing general conclusions from specific observations.
28
What is deductive reasoning?
Reaching specific conclusions from general observations/hypotheses.
29
What is the biosphere?
The entire portion of the Earth inhabited by life. The sum of the planets ecosystems.
30
What is an ecosystem?
- All the living things in an area along with the non-living, abiotic elements they interact with - One or more communities and the physical life around them.
31
What is a community?
- All the living things that inhabit a particular area - A collection of species living close enough to each other for possible interaction - Seen in things like food webs
32
What is a population?
- A group of species that all live in the same area, interbreed, and create fertile offspring
33
What is DNA?
Macromolecule that carries the genetic instructions used in the growth, development, functioning, and reproduction of all known living organisms
34
What are the four nitrogenous bases? Which pair? How many bonds between the pairs?
Adenine + thymine - 2 bonds Guanine + cytosine - 3 bonds
35
What are emergent properties?
Looking at the bigger picture to see new properties that weren't present in the previous level of the hierarchy.
36
What is a gene?
A stretch of DNA that encode all info to build molecules synthesized in a cell, that establish the cell's identity.
37
What do many genes create instructions for?
Proteins! Which serve a variety of purposes.
38
What is gene expression?
The process by which the info encoded in DNA directs the synthesis of proteins. (or RNAs)
39
What is transcription?
Process that transcribes DNA sequences into RNA.
40
What is translation?
Translates RNA into amino acids --> proteins
41
What are the rules around writing properly for binomial nomenclature?
Genera (genus) name and specific epithet (species) name. Genus is capitalized, species is not. Both are italicized (or underlined while writing by hand)
42
What does a taxon name contextualize?
A taxon name is a hypothesis about the distribution of variation in nature and the organisms' place within the tree of life.
43
What can we say about Domain Bacteria?
Most diverse domain
44
What can we say about Domain Archaea?
Survive extreme elements
45
What kingdoms are included under Domain Eukarya?
Kingdom Plantae Kingdom Animalia Kingdom Fungi Protists
46
What are the two primary methods scientists use to determine links between life?
- Similar morphological (structure) characteristics - Similar molecular characteristics
47
What does LUCA stand for?
Last universal common ancestor.
48
What is monophyletic grouping?
A clade is monophyletic when it consists of the ancestor species and all of its descendants.
49
What is paraphyletic grouping?
Consists of the ancestor species and some but not all of its descendants.
50
What is polyphyletic grouping?
Includes distantly-related species but not the most recent common ancestor.
51
What is abiogenesis?
A theory in the evolution of early life on Earth whereby organic molecules and subsequent simple life forms first originated from **inorganic substances**
52
What are some of the key events in life's history?
- Origin of life (small organic molecules...) - Emergence of single-celled organisms (prokaryotes, eukaryotes) - Emergence of multi-celled organisms - Colonization of land
53
What/when is the earliest direct evidence of life?
~3.7 bya - stromatolites: layered rocks that form when prokaryotes bind thin films of sediment together
54
What happened ~3.0 bya?
- Ancestors of modern cyanobacteria (aka blue-green algae) lived on the Earth. - Oxygen revolution!
55
When were prokaryotes the Earth's sole inhabitants?
~3.7 - ~1.8 bya
56
When did the first eukaryote emerge?
~1.8 bya
57
When did multicellular organisms emerge?
~1.2 bya
58
When did anthropods emerge?
1 bya
59
When did plants emerge?
0.8 bya
60
When did chordates emerge?
0.6 bya
61
62
What happened during the Cambrian period? (paleozoic)
Sudden increase in diversity of many animal phyla (Cambrian explosion!) ~541 mya
63
What happened during the Ordovician period? (paleozoic)
Marine algae abundant: colonization of land by diverse fungi, plants, and animals. ~485 mya
64
What happened during the Silurian period? (paleozoic)
Diversification of early vascular plants. ~444 mya
65
What happened during the Devonian period? (paleozoic)
Diversification of bony fishes; first tetrapods and insects appear
66
What happened during the Carboniferous period? (paleozoic)
Extensive forests of vascular plants form; first seed plants appear; **origin of reptiles**; amphibians dominant
67
What happened during the creataceous period?(mesozoic)
Flowering plants appear and diversify; many groups of organisms, including dinosaurs, become extinct at the end of this period.
68
What is the cell?
The basic structural and functional unit of every organism
69
What are things that all cells have?
- A plasma membrane - A semi-fluid substance called a cytosol - DNA - Ribosomes (to make proteins) - Perform all activities required for life
70
What is the plasma membrane?
- A selective barrier - A phospholipid bilayer (with hydrophyllic heads and hydrophopic tails) - Allows passage of oxygen, nutrients, and waste - Restricts passage of other substances - Glycolipids help with structural integrity
71
What is the nucleus?
- Membrane-bound organelle that contains most of the cell's DNA
72
What is the nuclear envelope?
- Lipid bilayer that encloses the nucleus
73
What is a nucleotide? What is it made up of?
- The building blocks of DNA - Contains phosphate group, sugar, and a nitrogenous base
74
What type of bonds are the bonds between nucleotides?
Hydrogen bonds
75
What is a histone?
Proteins that help to condense the DNA into chromatin
76
What is a nucleosome?
DNA wrapped around a core of (8) histones.
77
What is a chromatid?
Nucleosomes winded up together
78
What is a chromosome?
2 chromatids
79
What are ribosomes?
- Carry out protein synthesis - Comprised of ribsomal RNA and protein
80
What is the endoplasmic reticulum?
- Continuous with the nuclear envelope - Consists of rough (filled with ribosomes) and smooth (no ribosomes) ER
81
What does the smooth ER do?
- Lipid & steroid synthesis - Carbohydrate metabolism - Calcium storage - Detoxification
82
What does the rough ER do?
Protein synthesis! (which makes sense because they have the ribosomes attached)
83
What is the Golgi apparatus?
- Sorts, modifies, and directs proteins and lipids to final destination (aka shipping/receiving centre) - Makes lysosomes and vesicles - Consists of flattened membranous stacks called cisternae
84
What is the mitochondria?
- The site of aerobic respiration (use oxygen to produce energy) - Contains outer and inner membranes (matrix within the inner membrane)
85
What is the cytoskeleton?
- A network of fibers that extends throughout the cytoplasm
86
What are microtubules?
- An important part of chromosome seperation during cell division - Microtubules grow out from a centrosome near the nucleus
87
What structures are unique to plant cells?
- Chloroplasts - Large, central vacuole - Cell wall - Plasmodesmata (plant cell highway)
88
What are chloroplasts?
- The site of photosynthesis (energy from sunlight used to produce glucose from CO2 and water)
89
What does the large, central vacuole do?
- Holds organic compounds (like wastes) and water
90
What does the cell wall do?
- Maintains cell shape - Prevents excessive water uptake
91
What is the plasmodesmata?
- Channels between plant cells
92
What is cell division necessary for in multicellular organisms?
- Growth and development - Repair
93
True or false: most cell division results in daughter cells with identical genetic information as the parent cell (and each other).
True, for mitosis! The exception would be meiosis.
94
What is mitosis? What is its function?
Division which results in two cells that are genetically identical to each other. Its function is growth or repair.
95
What is meiosis? What is its function?
Division that results in gametes with 1/2 the amount of genetic material of the original cell. Its function is producing gametes for sexual reproduction.
96
What is cell division called for bacteria and archaea?
Binary fission
97
How many sets of chromosomes do somatic cells have?
2 sets (2n, diploid)
98
How many sets of chromosomes do gametes have?
1 set! (n, haploid)
99
What is a karyotype?
A visual representation of a complete set of chromosomes in a cell.
100
What is chromatin?
DNA plus proteins (including histones) Long, stringy DNA
101
What does condensed chromatin turn into?
A chromosome! It's a higher order of DNA organization
102
What is a centromere?
Where two sister chromatids come together
103
What are the phases of the cell cycles?
- Miotic (M) phase (mitosis and cytokinesis) - Interphase (G1, S, G2)
104
What are the 5 phases of mitosis?
- Prophase - Prometaphase - Metaphase - Anaphase - Telophase
105
What happens during G2 of Interphase (mitosis)?
- Nuclear envelope encloses nucleus - Nucleus contains one of more nucleoli - Two centrosomes form - Chromosomes, duplicated during S phase, cannot yet be seen because they are not yet condensed
106
What happens during prophase of mitosis?
- **Chromatin fibers condense** - Nucleoli disappear - Duplicated chromosomes appear as sister chromatids joined at centromeres - Mitotic spindle begins to form - Centrosomes move away from each other
107
What happens during prometaphase of mitosis?
- Nuclear envelope usually fragments (microtubules invade nuclear area) - Chromosomes condense further - Each chromatid now has a kinetochore (structure of proteins attached to the centromere that links each sister chromatid to the mitotic spindle) - Microtubules attach to kinetochores - Nonkinetochore microtubules interact with those from opposite pole of spindle
108
What happens during metaphase?
- Centrosomes at opposite poles - Chromosomes have arrive at the metaphase plate - Kinetochores of sister chromatids are attached to kinetochore microtubules coming from opposite poles
109
What happens during anaphase?
- Two sister chromatids seperate = each chromatid becomes a seperate chromosome - Daughter chromosomes move toward opposite ends of the cell - Nonkinetochore microtubules lengthen - cell elongates
110
What happens during telophase?
- Two daughter nuclei form in the cell - Nucleoli reappear - Chromosomes become less condensed - Spindle microtubules are depolymerized - Mitosis is complete
111
What is cytokinesis?
- In animal cells, cytokinesis occurs as a process called cleavage - In plant cells, a cell plate forms - Division of cytoplasm is well underway by late telophase
112
How are genes passed to the next generation?
Through gametes (sperm and eggs)
113
What are homologous chromosomes?
- Homologous chromosomes are two chromosomes of a pair - Same length, centromere position, gene position - They both carry genes controlling the same inhertited characters (and the position is the same) but they may contain different alleles - One from the maternal side, one from the paternal side
114
What is an allele?
A variant form of a gene
115
What does homozygous mean?
Both alleles of the gene at the locus on the homologous chromosome are the same
116
What does heterozygous mean
Alleles of the gene at the locus on the homologous chromosome are different
117
When does the human life cycle begin?
When the sperm fuses with an egg
118
What does the union of gametes result in?
Fertilization, with the resulting zygote being diploid
119
What happens in prophase I of meiosis?
- Homologous chromosomes pair up, **cross over**, and condense - Centrosomes move - Spindles form - Nuclear envelope breaks down - Microtubules attach to kinetochores
120
What are the points of attachment where crossovers occur called?
Chiasmata
121
What happens during metaphase I in meiosis?
- Pairs of homologous chromosomes are arranged at metaphase plate - Homologs are attached to kinetochores (one from each pole)
122
What happens during anaphase I of meiosis?
- Cohesins break down, allowing homologs to seperate - Homologs move toward opposite poles by the spindle - Chromatids still attached via centromere
123
What happens during telophase I of meiosis?
- When this phase begins, each half of the cell has a haploid set of duplicated chromosomes - Cytokinesis occurs
124
What happens during prophase II of meiosis?
- Spindle apparatus forms - Chromosomes are comprised of two chromatids, joined at the centromere
125
What happens during metaphase II in meiosis?
- Chromosomes positioned at metaphase plate - Kinetochores of sister chromatids are attached to microtubules extending from opposite poles
126
What happens during anaphase II in meiosis?
- Breakdown of proteins holding the sister chromatids together allows them to seperate - Chromatids move toward opposite poles as individual chromosomes
127
What happens during telophase II in meiosis?
- Nuclei form - Chromsomes decondences - Cytokinesis occurs - Meiotic division of one parent cell produces four daughter cells, each with a haploid set of unduplicated chromosomes
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