Unit 1 Flashcards
what does CHARRGED stand for
Cell, Homeostasis, Adapts, Responds, Reproduces, Grows, Energy, DNA
what are the 8 processes IB wants you to know
Metabolism, Response to Stimuli, Homeostasis, Movement, Growth, Reproduction, Excretion, Nutrition
what is biology
bio- life // ology- the study of
Charrged (cells)
living things are made up of one or more cells // organisms can be unicellular (made of one cell) or multicellular (made of more than one cell)
chArrged (adapt/evolve)
over generations, groups of living things change over time (because their genetic information changes). this is known as adaptation and evolution
cHarrged (homeostasis)
the ability to maintain a constant internal environment is called maintaining homeostasis
chaRrged (response)
organisms notice and react to stimuli from their environment // reacting to stimuli (changes in the environment) can often lead to movement
charRged (reproduce)
all living things make new, similar, living things
charrGed (grow)
every organism has a pattern of growth and development
charrgEd (energy)
all living things must take in materials & energy // many chemical reactions occur within living things in order to build up and break down materials to facilitate these processes. all of these chemical reactions together are known as “metabolism”
charrgeD (DNA)
all living things store the information they need to live, grow, and reproduce in a genetic code written in a molecule called DNA
3 things about cell theory
- all living things are made of one or more cells
- cells are the basic unit of life
- cells come from pre-existing cells
3 things about the conditions on early earth
- early earths atmosphere lacked free oxygen & ozone and had an abundance of CO2 and CH4 (carbon dioxide & methane)
- without ozone, there was more UV light that reached the surface of the earth
- CO2 & CH4 are greenhouse gases - gases that trap heat - increasing the temperature of early earth
miller and urey’s experiment
created an experiment to stimulate the conditions on prebiotic earth they investigated what types of molecules could form in the conditions of early earth (combined H2O, CH4, NH3, and H2 with heat and electricity: under these conditions, several simple organic molecules, including amino acids were found)
formation of the first cells
- the first cells (proto cells) had to have formed spontaneously and in an aqueous environment
- self-replication of molecules and self-assembly of cells were necessary for the evolution of the first cells
- protocells must have been significantly less complex than current cells
spontaneous formation of vesicles
- when in an aqueous environment, fatty acids will spontaneously self-assemble to form spherical bilayers
- the spherical bilayer forms a membrane that separates the internal environment from the external environment
what does RNA stand for
ribonucleic acid
what is RNA thought to be
RNA is thought to have been the first genetic material - not only can RNA act as genetic material, but it also has catalytic properties
what does LUCA stand for
Last Universal Common Ancestor
what is the evidence for LUCA
- universal genetic code
- conserved genes across all organisms
what was LUCA likely to be
a unicellular, autotrophic, microbe that existed between 2.5 and 3.5 billion years ago
LUCA and hydrothermal vents
- fossilized evidence suggests that LUCA could have evolved around the hydrothermal vents
- hydrothermal vents remain a hotbed of life even today
- organisms thrive in the mineral rich environment surrounding the vents
COMPARISONS of prokaryotic and eukaryotic cell structure
- have DNA
- have a cell membrane
CONTRASTS of prokaryotic and eukaryotic cell structure
- prokaryotic cells have flagellas whereas eukaryotic cells do not
- eukaryotic cells have a nucleus whereas prokaryotic cells have a nucleoid
what kind of cells have ribosomes
all of them
what is the difference between eukaryotic and prokaryotic ribosomes
prokaryotic cells: 70s // eukaryotic cells: 80s
eukaryotes include…
plants, animals, fungi, protists
inside of an animal cell
- a place where the cells activities are controlled
- a place where chemical reactions happen
- a place where substances can pass in and out of the cell
- a place where energy is release for the cell
inside of a plant cell
- same features as animal cells
- a place where light is captured for photosynthesis
- a place where water & other materials are stored
- a place to help support and strengthen the cell
both type of cells have these:
mitochondria, ribosomes, nucleus, cell membrane, cytoplasm
only plant cells have these
central vacuole, chloroplasts, cell wall
what is a flagella
lash-like appendage that protrudes from the cell body
what is a cilia
slender protuberances that project from the much larger cell body
atypical cell structure in eukaryotes
numbers of nuclei illustrate one type of atypical cell structure in aseptate fungal hyphae, skeletal muscle, red blood cells, and phloem sieve tube elements
aseptate fungal hyphae
- challenges the idea that a cell is a single unit
- fungal hyphae are very large, forming a tubular system with many nuclei and a continuous cytoplasm
- like muscle cells they are multi-nucleated
- they have cell walls composed of chitin
- the cytoplasm is continuous along the hyphae with no end cell wall or membrane
striated skeletal muscle
- challenges the idea that a cell has one nucleus
- muscle cells have more than one nucleus per cell
- muscle cells called fibres can be very long (300 mm)
- they are surrounded by a single plasma membrane but they are multi-nucleated (many nuclei)
- this does not conform to the standard view of a small single nuclei within a cell
red blood cells
- red blood cells have no nucleus when they are mature to allow for more hemoglobin storage
- red blood cells have no DNA and thus cannot replicate bone marrow must continually produce new RBC’s
- the atypical structure of RBC’s challenges the cell theory
phloem sieve tubes in plants
- sieve elements line the phloem in plants and are interconnected into tube assemblies that transverse the length of a plant
- these sieve tubes lack nuclei and have few organelles, relying on local companion cells for survival
- phloem sieve tubes challenge the idea that multicellular structures are composed of independent cells
endosymbiotic theory
- lynn margulis (1964)
- “eukaryotic cells evolved from prokaryotic cells”
- major organelles in eukaryotic cells are thought to have once been prokaryotic cells that established symbiotic relationships
- mitochondria & chloroplasts
evidence supporting endosymblosis
- mitochondria and chloroplasts have a double membrane
- mitochondria and chloroplasts have their own ribosomes
- mitochondria and chloroplasts have circular DNA
- mitochondria and chloroplasts reproduce independently of the rest of the cell and in a way that is similar to binary fission
why is it thought that what is now mitochondria, was engulfed first, then what is now chloroplasts was engulfed
if the chloroplast came first, then some cells would have had to lose their chloroplasts, then they all would have had to engulf the mitochondria
organic chemistry = carbon chemistry
- the study of compounds that contain carbon
- organic molecules range from simple to colossal
carbon - selection of life
- although cells are 70-95% water, the rest consists mostly of carbon-based compounds
- carbon is the best element for building large, complex molecules
- all molecules that distinguish living matter are carbon compounds
tetravalence
an atom with four “empty” valence electron “spots”
carbon atoms form diverse molecules
- electron configuration determines the kinds and number of bonds an atom will form with other atoms
- with four valence electrons, carbon can form up to four covalent bonds with a variety of atoms
- this tetravalence makes large, complex molecules possible
hydrocarbons
molecule consisting only of carbon and hydrogen, they are nonpolar (because carbon’s and hydrogen’s electronegativites are very similar)
what are biological molecules made from
hydrocarbon frames and have functional groups that can make the molecules polar
most hydrocarbons have many what kind of bonds
covalent
carbon molecular diversity
carbon chains vary in length and shape (because of tetravalence)
why is carbon so necessary for life?
- form stable bonds with many elements, including itself
- form a huge variety of very large complex molecules
- carbon is small enough to form bonds with other carbons (making chains) and to form bonds with other atoms
what is hydroxyl found in
carbohydrates, proteins, nucleic acids, lipids
what is carboxyl found in
proteins, lipids
what is amino found in
proteins, nucleic acids
what is phosphate found in
nucleic acids
what are biological macromolecules
carbon based molecules
what are the 4 classes of biological macromolecules
- carbohydrates
- lipids
- proteins
- nucleic acids
how do macromolecules build up and break down
metabolism
metabolism
- refers to all of the chemical reactions that occur in a cell
- this includes anabolic and catabolic reactions/pathways
- anabolic reactions/pathways BUILD complex molecules from simpler molecules
- catabolic reactions/pathways BREAK down complex molecules into simpler molecules
macromolecule structure
most macromolecules (such as nucleic acids) are polymers
monomers
the small building-block molecules
polymer
a long molecule consisting of many similar building blocks
anabolic pathways
- the synthesis (making) of complex molecules from simpler molecules
- “building up”
polymers are built through…
anabolic pathways
what is the specific reaction of a polymer
condensation reaction (aka dehydration synthesis)
when does condensation/dehydration synthesis occur
when two monomers join as they lose a water molecule
enzymes
macromolecules that speed up the anabolic process
catabolic pathways
- the breakdown of complex molecules into simple molecules
- “breaking down”
to break apart a polymer
- catabolic pathways
- hydrolysis: a reaction that disassembles polymers to create monomers
- a reaction that is the opposite of dehydration synthesis
what is hydrolysis
hydro- water // lysis- split
how to remember anabolism vs catabolism
ana builds, the cat breaks
nucleic acids - basic structure
- monomer: nucleotide
- polymer: polynucleotide :nucleotides are connected together by phosphodiester bonds in a polynucleotide :a polynucleotide strand has direction
- function: store, access, and transmit genetic information
- 2 examples: DNA, RNA
pentose sugars
there are two types of pentose sugars that are found in nucleotides
- deoxyribose
- ribose
the difference is that deoxyribose lacks an oxygen on the 2’ carbon (just a -H instead of an -OH)
nucleotide structure
3 parts
- phosphate group
- 5 carbon (pentose) sugar
- nitrogen base
elements
-C, H, O, N, and phosphorus
DNA nitrogen bases
Adenine with Thymine, Guanine with Cystosine
RNA nitrogen bases
Adenine with Uracil, Guanine with Cytosine
purines
2 rings
A & G
pyrimidines
1 ring
C & T & U
are DNA strands antiparallel or complimentary
antiparallel
what does DNA stand for
deoxyribonucleic acid
if a nucleotide is a “generic nucleotide”, what should you name it?
pentose sugar
if you are labeling a DNA nucleotide, what would you label it?
deoxyribose
if you are labeling an RNA nucleotide, what would you label it?
ribose
what holds the 2 strands together in DNA
hydrogen bonds
how are nucleotides connected
phosphodiester bonds
what is a hydrogen bond
it is a weak attraction between a slightly positive hydrogen, and a slightly negative atom
what do you call the pairings A & T and C & G
complementary base pairing
purine + purine + ?
too wide (A/G pair)
pyrimidine + pyrimidine = ?
too narrow (C/T pair)
purine + pyrimidine = ?
width consistent with x-ray data
hydrogen bonds compatibility
it is like puzzle pieces, the hydrogen bonds have to line up and be compatible
carbon labeling
gives us a way to talk about the ends of the strands since they are different
how are carbons in the sugar labeled
1’, 2’, 3’, 4’, and 5’
1’ is attached to the bast, and the 5’ carbon is attached to the phosphate group (counterclockwise)
where was genetic material found
in the nucleus of eukaryotic cells
where are the 2 biological macromolecules that are found in the nucleus
nucleic acids and protein
why did scientists initially think that proteins were the genetic material
there are over 20 different amino acids (monomers of proteins) and only 4 different nucleotides in DNA
who were hershey and chase
they studied bacteriophages and knew that they infect bacteria by injecting their genetic material as well has containing a protein shall and nucleic acid core
conclusion: confirmed that DNA was the genetic material because it was injected into the bacterial cells
who is chargaff
look at the proportions (%) of the different bases in DNA of different species
what were chargaff’s 2 major conclusions
- different species have different % of each base
- in any species:
- the amount of adenine was roughly equal to the amount of thymine (A = T)
- the amount of guanine was roughly equal to the amount of cytosine (C = G)
A + G = T + C
who is rosalind franklin
- used x-ray crystallography to take images of DNAA
- photo 51 showed that DNA was a double helix
- rosalind didn’t want to share her finding without additional evidence
wilkins (also had to work on DNA imaging) shared photo 51 with james watson without rosalinds knowledge
who are watson and crick
- used rosalind’s research and cargaff’s data to create the double helix model of DNA
- published a paper in nature in 1953
why did rosalind franklin not receive the nobel piece prize
- in 1962, watson, crick, and wilkins were awarded the noble piece prize in physiology or medicine for their discovery of the structure of DNA
- rosalind franklin died in 1958, so she did not receive the noble prize for her contribution to this discovery
