final exam Flashcards
What are the 7 key characteristics of life?
Grows Reproduces Responds to its environment Maintains homeostasis Evolves Has DNA Composed of cells
All life came from a single source (or a small number of sources)
Unity of Life
Organsims adapted to their environments over many generations
Diversity of Life
What are the hierarchal levels of life?
Atoms>molecules>organelles>cells>tissues>organs>organ systems>organsims
- All living things are made up of cells
- The cell is a structural and functional unit of all living things
- All cells come pre-existing cells
- Cells contain hereditary information which is passed from cell to cell during cell division
- All energy flow of life occurs within cells
- All cells are basically the same in chemical composition
Cell Theory
Has a nucleus, large cells or multicellular, DNA in strands
Eukaryotic Cells
No nucleus, small cells, circular DNA
Prokaryotic Cells
One organism
Individual
All the living organisms of one species in a particular area
Population
All species in an area (plants, animals, decomposers…)
Community
Living and non-living components of an area
Ecosystem
All life on Earth in all the places that life exists
Biosphere
New properties arise at each level of organization
Emergent Properties
The water molecules stick to each other, water has surface tension
Cohesion
Water sticks to certain other materials, wall of plant veins
Adhesion
Water loving
Hydrophilic
Water hating
Hydrophobic
What are the 4 main classes of organic molecules?
Carbohydrates, lipids, proteins, nucleic acids
What is the monomer of carbohydrates?
monosaccharide
What is the polymer(s) of carbohydrates?
Disaccharides (2), polysaccharides (3+)
What is the monomer of lipids
1 glycerol+3 fatty acids
What is the polymer of lipids?
Triglyceride
What is the monomer of proteins?
Amino acid
What is the polymer of proteins?
Peptides
What is the monomer of nucleic acids?
Nucleotide
What is the polymer of nucleic acids?
Nucleic Acid
Created by removing water and getting a larger polymer
Dehydration Synthesis
Break with water
Hydrolysis
The order of amino acids
Primary Structure
Stabilized by hydrogen bonds
Secondary Structure
The overall shape of a protein molecule
Tertiary Structure
Occurs in proteins formed of 2 or more peptide subunits
Quaternary Structure
The total amount of energy in the universe is constant
- Energy cannot be created or destroyed
- Energy can only be changed from one form to another
- Plants convert light energy to chemical energy via photosynthesis
First Law of Thermodynamics
The entropy (degree of disorder) is always increasing
- Energy is lost when it is transformed from one form to another
- Energy is generally lost as heat
Second Law of Thermodynamics
Releases energy, products low in potential energy
Exergonic Reactions
Absorbs energy, products rich in potential energy
Endergonic Reactions
What is the relationship between enzymes and activation energy?
Enzymes lower activation energy
What denatures an enzyme?
Changes in pH, temperature, and salt concentration
Is an enzyme used up during a reaction?
No
- Showed that killed pathogenic bacteria could transfer virulence to non-pathogenic bacteria
- This newly acquired trait of pathogenicity was inherited by all of the descendants of the transformed bacteria
Frederick Griffith
Identified the transforming substance as DNA
Avery, McCarty, MacLoed
Concluded that the DNA injected by the phage must be the molecule carrying the genetic information that makes the cells produce new viral DNA and proteins
-Provided powerful evidence that nucleic acids, rather than proteins, is the hereditary information
Hershey and Chase
Chargaff’s Rules, A=T, C=G
Erwin Chargaff
- Made an X-ray diffraction photograph of DNA which showed the helical structure
- Concluded that the sugar-phosphate backbone was on the outside
- Died in 1958
Rosalind Franklin
- Determined base pairing
- Determined the two strands of DNA were involved–double helix
- Determined the strands ran in opposite directions–antiparallel
Watson and Crick
Breaks hydrogen bonds between complementary pairs (unzips DNA)
Helicase
Adds a RNA primer to initiate replication
Primase
Adds DNA molecules to pre-existing chain from 5’ to 3’ on the growing chain
DNA Polymerase
Adds nucleotides after RNA primer
DNA Polymerase III
Removes RNA primer
DNA Polymerase I
Joins Okazaki fragments
DNA Ligase
Helps with the untwisting of DNA
Topoisomerase
Binds to the single strands to keep them from rejoining
Single Strand Binding Protein
The new complementary DNA strand synthesized continuously along the template strand
Leading Strand
A discontinuously synthesized DNA strand that elongates by means of Okazaki fragments
Lagging Strand
Pries two strands of DNA apart and joins together RNA nucleotides complementary to the DNA template
RNA polymerase
DNA sequence where RNA polymerase attaches
Promoter
DNA sequence where RNA polymerase attaches
Terminator
What is produced from transcription?
mRNA
What is the ‘one gene-one enzyme’ hypothesis?
Each mutated gene must normally dictate the production of one enzyme
How does transcription vary in prokaryotes vs eukaryotes?
Prokaryotes produce mRNA, eukaryotes produce pre-mRNA
mRNA removed before transcription
Introns
Remaining mRNA to be used during translation
Exons
The process of remaining introns in the nucleus
RNA Splicing
Small nuclear ribonucleoproteins
- Composed of snRNA and proteins
- Recognize introns
snRNPs
A ribozyme, a catalyst that is a RNA molecule, not an enzyme
snRNA
Consists of snRNP subunits
-Bind to pre-mRNA at multiple sites along the intron, snip the intron, and join the exons
Spliceosome
Messenger RNA, carries the codon from the DNA to the ribosome
mRNA
Transfer RNA, brings amino acids to the ribosome
tRNA
Ribosomal RNA, components of ribosomes, most abundant RNA
rRNA
Structural components of spliceosomes which remove introns from eukaryotic pre-mRNAs
snRNA
Joins an amino acid to tRNA
Aminoacyl-tRNA synthetase
The messenger RNA nucleotide triplets
Codon
Base pairs with the complementary codon on the mRNA
Anticodon
Signals the start of translation
Start Codon
Signals the end of translation
Stop Codon
tRNA with the polypeptide moved to the p-site, empty tRNA moved to the e-site and released
Translocation
Contains a mRNA binding site
Small Subunit
Lines up the tRNA
Large Subunit
Holds the tRNA carrying the growing polypeptide chain
P-site
Holds the tRNA carrying the next amino acid
A-site
Discharges tRNA
E-site
Change in single nucleotide
Point Mutation
Point mutation in the third base pair of a codon that does not change the amino acid
Silent Mutation
Point mutation that does change the amino acid
Missense Mutation
Point mutation that replaces an amino acid with a stop codon
Nonsense Mutation
Additions of one or more nucleotides in a gene
Insertion
Deleting of one or more nucleotides in a gene
Deletion
Insertions or deletions of one or two nucleotides resulting in a shift in the reading frame
Frameshift Mutation
Physical or chemical agents that cause mutations
-e.g. UV light, X-rays, most carcinogens
Mutagen
Transcription is usually turned on, but can be inhibited
- Repressor normally unbound
- Corepressor needed in order for the repressor to bind to the operator
Repressible Operon
Transcription is off, but can be stimulated
- Repressor normally bound to the operator
- Inducer required to inactivate the repressor so transcription can occur
Inducible Operon
The switch on the DNA that allows transcription to occur
Operator
Binds to the operator and blocks the attachment to the promoter
Repressor
Codes for repressors
Regulatory Gene
Binds to a repressor protein and changes the protein’s shape, allowing it to bind to the operator and switch an operon off
Corepressor
Binds to a repressor and changes the repressor’s shape so it cannot bind to an operator
Inducer
A protein that binds to other proteins to mark them for degradation
Ubiquitin
Recognize the ubiquitin-tagged proteins and break them down
Proteasomes
- Makes copies of DNA
- Can copy the DNA when the original DNA source is limited or impure
- Selective of specific sequences
- After 30 cycles, a billion copies of target sequence are present
PCR
The DNA is inserted into its plasmid
Bacteria Cloning
Differentiated cells can be grown into complete new plants
Plant Cloning
Use mammary cells as DNA source
Animal Cloning
Using fluorescent dyes to see where genes are expressed
In situ hybridization
Examines a large number of genes from a small tissue sample
- Examines mRNA
- Detects presence and intensity
- Screens 1000s of genes at a time
- Requires prior knowledge of the genome
Microarrays
Unspecialized cells that can reproduce itself indefinitely and also differentiate into specialized cells
Stem Cells
Introducing genes into an afflicted individual for therapeutic purposes
Gene Therapy
The study of whole sets of genes and their interactions
Genomics
Why do viruses ‘lead a borrowed life’?
They need a host cell to replicate
Culminates in the death of the host cell and release of new viruses
Lytic Cycle
Viral DNA is replicated without killing the host cell
Lysogenic Cycle
What is the advantage of a membrane coat?
Protection
What causes a virus to become pandemic?
A virus spread to more than 1 continent
How can we prevent viral diseases?
Vaccines
Regulates flow of molecules into and out of the cell
Cell Membrane
- Contains genetic material (DNA)
- Components: nucleolus, nuclear membrane, chromatin
Nucleus
Protein synthesis
Ribosomes
Covered with ribosomes, functions in protein synthesis
Rough ER
Functions in lipid metabolism, synthesis of cholesterol and steroid hormones
Smooth ER
- Modifies proteins and lipids received from the ER
- Sorts proteins and lipids for final destinations
- Packages and exports proteins and lipids in vesicles
- In plants, it manufactures polysaccharides
Golgi Apparatus
Controlled intracellular digestion of macromolecules, has a pH of 5, only in animal cells
Lysosomes
A membrane sac in the cytoplasm of a eukaryotic cell
Vesicle
Pumps excess water from cell, only in plant cells
Vacuole
Energy factories, site of cellular respiration, has its own DNA
Mitochondria
In plants, where photosynthesis occurs
Chloroplasts
Produces hydrogen peroxide as a byproduct, breaks down fatty acids, alcohol
Peroxisomes
Serves a variety of mechanical, transport, and signaling functioning
Cytoskeleton
Composed of cellulose, only in plants Functions: 1. Protects the cell 2. Provides shape 3. Prevents uptake of excess water 4. Holds the plant up against gravity
Cell Wall
What cell organelles are unique to plants?
Cell wall, vacuole, chloroplasts, plasmodesmata
What cell organelles are unique to animals?
Lysosomes, centrioles, cell junctions
Evolutionary origins of mitochondria and chloroplasts
Endosymbiont Theory
What organs are in the endomembrane system (6)?
ER, nuclear envelope, golgi, lysosomes, vesicles, vacuoles
Proteins may move laterally, they don’t flip flop
-If correct, proteins from two different cells will mix
Fluid Mosaic Model
What are the functions of the cell membrane? (6)
Transport Enzyme activity Signal transduction Cell-cell recognition Intercellular joining Attachment to cytoskeleton and extracellular matrix
The diffusion of free water across a selectively permeable membrane
Osmosis
Movement of molecules down their concentration gradient
Diffusion
The movement of ions or molecules across a cell membrane into a region of higher concentration
Active Transport
Proteins that carry substances from one side of the membrane to the other
Carrier Protein
Facilitate the transport of substances across a cell membrane
Channel Protein
Higher solute concentration, water flows out of the cell and it shrinks, then will shrivel
Hypertonic
Lower solute concentration, water flows into the cell and it expands, cell will swell and may burst
Hypotonic
Equal tonicity
Isotonic
One unit of condensed chromatin
Chromatid
A cellular structure that has 1 DNA molecule and associated proteins
Chromsome
Pair of separate DNA strands that carry genes for the same traits
Homologous pair
Two copies of a duplicated chromosome attached at the centromere end
Sister Chromatid
The region on each sister chromatid where it is most closely attached to the other chromatid
Centromere
Cell has homologous pair of chromosomes
Diploid
Cell has single chromatids or sister chromatids
Haploid
Microtubule organizing center
Centrosome
A cable composed of actin proteins in the cytoplasm of eukaryotic cells
Microfilament
Composed of tubulin proteins
Microtubule
Proteins associated with DNA at the centromere
Kinetochore
Normal cell operations and cell growth
G1
Preparation for cell division
G2
Replication of DNA
S
Chromatin condense becoming sister chromatids, nucleus dissolves
Prophase
Sister chromatids line up in the middle of the cell
Metaphase
Sister chromatids separate
Anaphase
The cells start to separate (in animals, a cleavage furrow forms)
Telophase
How does cell division proceed in prokaryotes?
Binary fission
Duplicate homologous chromosomes pair and exchange segments
Prophase I
Homologous pairs line up
Metaphase I
Homologous pairs separate
Anaphase I
Two haploid cells form, each chromosome still has 2 sister chromatids
Telophase I
A spindle apparatus forms
Prophase II
Sister chromatids line up
Metaphase II
Sister chromatids separate, the chromatids move toward opposite poles as individual chromosomes
Anaphase II
Nuclei form, the chromosomes begin decondensing and cytokinesis occurs
Telophase II
Always expressed, capital letter
Dominant Trait
Only expressed when the dominant is not present, lowercase letter
Recessive Trait
Only on the X chromosome
X-Linked Traits
Both traits expressed
Co-Dominance
Blending of traits
Incomplete Dominance
An allele that is lethal in the homozygous condition
Homozygous Lethal
How do cells communicate when they are close in contact with each other?
Cell junctions, cell-cell recognition
How do cells communicate over short distances?
Paracine signaling, synaptic signaling
A secreting cell acts on nearby target cells by discharging molecules of a local regulator into the extracellular fluid
Paracine Signaling
A gap between adjacent nerve cells
Synapse
How do cells communicate over long distances?
Relies on the bloodstream to transport molecules
What are the 3 stages of cell signaling?
Reception, transduction, response
A signal molecule binds to a receptor protein
Reception
Receptor protein is changed
Transduction
Specific response could be activating an enzyme, rearranging the cytoskeleton, or activating specific genes in the nucleus
Response
Glucose is oxidized into pyruvate -Occurs in all cells -Anaerobic process -Occurs in the cytosol Net reaction: -Glucose--> 2 pyruvate -Yields 2 ATP+ 2 NADH
Glycolysis
- Pyruvate leaves the cytosol and enters the mitochondria matrix via active transport
- Pyruvate is converted into Acetyl CoA
- Net reaction:
- 2 pyruvate +2 CoA–> 2 Acetyl CoA+2 CO2
- Yields 2 NADH
Pyruvate Oxidation
Produces virtually all the carbon dioxide resulting from cellular respiration
Net reaction:
-2 Acetyl CoA–> 4 carbon dioxide
-Yields 2 ATP, 6 NADH, 2 FADH2
Citric Acid Cycle
NADH and FADH2 release their electrons and H+
-Electrons power the pumping of H+ against a concentration gradient
-H+ pumped from the matrix to the intermediate space
Net reaction: H+ gradient
Electron Transport Chain
H+ concentration gradient used to make ATP
-Yields 26-28 ATP total
Chemiosmosis
Transmembrane enzyme that makes ATP
ATP synthase
What is the relationship between the Laws of Thermodynamics and photosynthesis?
Energy flows but nutrients cycle– energy is not created nor destroyed, just transformed
What organisms photosynthesize?
Plants
What is the equation for photosynthesis?
energy+6CO2+6H20–>C6H12O6+6O2
The O in carbon dioxide, does it become the O in glucose or O2?
Both
The O in H2O, does it become the ) in glucose or O2?
O2
- Used: water
- Produced: O2, ATP, NADPH
- Location: thylakoid
Light Dependent Reactions
- Used: CO2, ATP, NADPH
- Produced: glucose
- Location: stroma
Light Independent Reactions
3 stages: 1. Carbon fixation 2. Reduction 3. Regeneration of CO2 acceptor Net reaction: -3 CO2-->3 GCP -Uses ATP and 6 NADPH
Calvin Cycle
