A2.1 HL only Flashcards

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1
Q

Prebiotic age

A

hypothetical set of conditions present on the Earth around 3.7 to 4.0 billion years ago

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2
Q

Proto-Earth

A

encompassing Earth in its first one billion years

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3
Q

Extraplanetary objects

A

an astronomical object that exists outside the Solar System.

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4
Q

Hadean Eon

A

the oldest eon and dates from 4.5–4.0 billion years ago. This time represents Earth’s earliest history, during which the planet was characterized by a partially molten surface, volcanism, and asteroid impacts

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5
Q

inorganic molecules

A

Inorganic molecules are generally simple and are not normally found in living things. Although all organic substances contain carbon , some substances containing carbon, such as diamonds, are considered inorganic

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6
Q

organic molecules

A

a complex molecule that is primarily made of carbon atoms bonded with other elements and/or other carbon atoms. All living things on Earth are composed of organic molecules

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7
Q

unicellular

A

composed of a single cell

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8
Q

multicellular

A

an organism that is made of many cells, such as plants, animals or fungi

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9
Q

organelles

A

a subcellular structure that has one or more specific jobs to perform in the cell

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10
Q

compartmentalization

A

the separation of the cell interior in distinct compartments with specific local conditions that allow the simultaneous occurrence of diverse metabolic reactions and processes

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11
Q

Subcellular components

A

specific structures that take on sets of tasks within the cell, or they can be local regions of the cell defined by the concentration of molecules or distinct physical characteristics and proportions

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12
Q

binary fission

A

the process of one cell simply dividing into two. It is most commonly used in archaea and bacteria, which are both prokaryotic organisms

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13
Q

mitosis

A

the process by which a cell replicates its chromosomes and then segregates them, producing two identical nuclei in preparation for cell division.

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14
Q

gametes

A

a reproductive cell of an animal or plant. In animals, female gametes are called ova or egg cells, and male gametes are called sperm

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15
Q

paradox

A

contradictory-yet-interrelated elements that exist simultaneously and persist over time

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16
Q

proto-cell

A

self-organized, endogenously ordered, spherical collection of lipidsproposed as a rudimentary precursor to cells

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17
Q

Spontaneous generation theory

A

hypothetical process by which living organisms develop from nonliving matter

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18
Q

LUCA

A

the hypothesized common ancestral cell from which thethree domains of life, the Bacteria, the Archaea, and the Eukarya originated

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19
Q

Primordial Soup Theory

A

if energy is added to the gases that made up Earth’s early atmosphere, the building blocks of life would be created

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20
Q

Polymerization

A

any process in which relatively small molecules, called monomers, combine chemically to produce a very large chainlike or network molecule, called a polymer

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21
Q

Miller-Urey experiment

A

experimentalsimulationconducted in 1953 that attempted to replicate the conditions ofEarth’s earlyatmosphereandoceansto test whetherorganicmoleculescould be created abiogenically, that is, formed fromchemical reactionsoccurring betweeninorganicmolecules thought to be present at the time

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22
Q

Scientific models

A

a physical and/or mathematical and/or conceptual representation of a system of ideas, events or processes

23
Q

Extraplanetary carbon compounds

A

organic compounds found on meteorites

24
Q

Panspermia theory

A

the concept that life may have originated elsewhere in the universe and reached Earth through space travel, potentially by microorganisms or even advanced extraterrestrial beings

25
Q

Monomers

A

atoms or small molecules that bond together to form more complex structures such as polymers

26
Q

Polymers

A

any of a class of natural or synthetic substances composed of very large molecules, called macromolecules, that are multiples of simpler chemical units called monomers

27
Q

covalent bonds

A

a chemical bond that involves the sharing of electrons to form electron pairs between atoms

28
Q

activation energy

A

The minimum energy required for a reaction to occur

29
Q

“RNA World” hypothesis

A

suggests that life on Earth began with a simple RNA molecule that could copy itself. The RNA world hypothesis suggests that life on Earth began with a simple RNA molecule that could copy itself without help from other molecules

30
Q

Phospholipids

A

a group of polar lipids that consist of two fatty acids, a glycerol unit and a phosphate group

31
Q

Hydrophilic head

A

phosphate group of a phospholipid

32
Q

Hydrophobic tails

A

fatty acid tails of a phospholipid

33
Q

Micelle

A

a collection ofamphiphilicsurfactant molecules that spontaneously aggregate in water in a concentration-dependent manner to produce a metastable aggregate

34
Q

Liposome

A

a tiny bubbled vesicle made up of similar material to a cell membrane and phospholipids, which are essential to the cell membrane

35
Q

lipid bilayers

A

a continuous double layer of lipid molecules in which membrane proteins are embedded

36
Q

Murchison meteorite

A

a meteorite that fell in Australia in 1969 near Murchison, Victoria. It belongs to a group of meteorites rich in organic compounds

37
Q

Ribozymes

A

catalytically active RNA molecules or RNA–protein complexes, in which solely the RNA provides catalytic activity

38
Q

Inferred evolutionary intermediate

A

steps in an evolutionary pathway that are assumed but there is no direct evidence of

39
Q

Prokaryotes

A

any organism that lacks a distinct nucleus and other organellesdue to the absence of internal membranes

40
Q

Bacteria

A

single-celled microorganisms that lack a nuclear membrane, are metabolically active and divide by binary fission

41
Q

Archaea

A

single-celled microorganisms with structure similar to bacteria. They are evolutionarily distinct from bacteria and eukaryotes and form the thirddomain of life

42
Q

Extremophiles

A

an organism that thrives inextreme environments. Extremophiles are organisms that live in “extreme environments,” under high pressure and temperature

43
Q

sedimentary rock

A

formed from pre-existing rocks or pieces of once-living organisms

44
Q

isotope

A

A form of a chemical element in which the atoms have the same number of protons (part of the nucleus of an atom) but with a different number of neutrons (part of the nucleus of an atom)

45
Q

half-life

A

The time required for a biological system, such as that of a human, to eliminate, by natural processes, half of the amount of a substance (such as a radioactive material) that has entered it

46
Q

Biomarkers

A

A biological molecule found in blood, other body fluids, or tissues that is a sign of a normal or abnormal process, or of a condition or disease

47
Q

Stromatolites

A

mineral structures built by microorganisms

48
Q

Hydrothermal vents

A

the result of seawater percolating down through fissures in the ocean crust in the vicinity of spreading centers or subduction zones

49
Q

mutation

A

a change in a DNA sequence

50
Q

Carcinogens

A

a substance, organism or agent capable of causing cancer

51
Q

Molecular clock

A

DNA and protein sequences evolve at a rate that is relatively constant over timeand among different organisms

52
Q

obligate anaerobe

A

organisms that can grow and survive only in the absence of oxygen

53
Q

chemoautotroph

A

an organism that takes inorganic chemicals and transforms it into energy