final exam Flashcards
what are the 7 characteristics of all living organisms?
- composed of cells
- complex and ordered
- respond to their environment
- can grow, develop, and reproduce
- obtain and use energy
- maintain internal balance
- allow for evolutionary adaptation
what are the levels of cells, organisms, and populations that a biologist can study?
cells
atoms –> molecule –> macromolecule –> organelle –> cell
organisms
tissue –> organ –> organ system –> organism
populations
population –> species –> community –> ecosystem –> biosphere
explain the scientific method and its components
- observation
- hypothesis formation
- prediction
- experimentation
- conclusion
properties of water
- water has a high specific heat
- water has a high heat of vaporization
- solid water is less dense than liquid water
define isotopes
- atoms of a single element that possess different numbers of neutrons
- radioactive isotopes are unstable and emit radiation as the nucleus breaks up
define isomers
two or more compounds with the same formula but a different arrangement of atoms in the molecule and different properties.
define dehydrogenation
a hydrogen atom is lost (1 electron, 1 proton)
aerobic respiration
final electron receptor is oxygen
C6H12O6+ 6O2 –> 6CO2+6H2O
anaerobic respiration
final electron acceptor is an inorganic molecule (not O2)
fermentation
final electron acceptor is an organic molecule
photosynthesis equation
6CO2+ 12H2O –> C6H12O6+ 6H2O +6O2
oxygenic photosynthesis is carried out by:
- cyanobacteria
- 7 groups of algae
- all land plants - cholorplasts
- only 1% of the solar energy that reaches the earth is captured by photosynthesis
eukaryotic cell cycle
- G1 (gap phase 1)
- primary growth phase, longest phase - S (synthesis)
- replication of DNA - G2 (gap phase 2)
- organelles replicate, microtubules organize - M (mitosis)
- subdivided into 5 phases - C (cytokenesis)
- separation of 2 new cells
interphase is steps 1-3
parts of mitosis
- prophase
- prometaphase
- metaphase
- anaphase
- telophase
cytokinesis in animal cells
- cleavage of the cell into equal halves
- animal cells – constriction of actin filaments produces a cleavage furrow
meiosis division
meiotic cells have an interphase similar to mitosis. After interphase, germ-line cells enter meiosis 1.
prophase 1 & 2
metaphase 1 & 2
anaphase 1 & 2
telophase 1 & 2
mendel’s experimental method
- produce true-breeding strains for each trait
- cross-fertilize true-breeding strains having alternate forms of a trait
- allow the hybrid offspring to self-fertilize for several generations and count the number of offspring showing each form of the trait
usually 3 stages
F1 generation
- first filial generation
- offspring produced by crossing 2 true-breeding strains
- for every trait mendel studied, all F1 plants resembled only 1 parent
- referred to this trait as dominant
- alternative trait was recessive
F2 generation
- second filial generation
- offspring resulting from the self-fertilization of F1 plants
- although hidden in the F1 generation, the recessive trait had reappeared amoong the some F2 individuals
- Always found to be 3:1 ratio
principle of segregation
- “mendel’s first law of heredity”
- 2 alleles for a gene segregate during gamete formation and are rejoined at random, 1 from each parent, during fertilization
- physical basis for allele segregation is the behavior of chromosomes during meiosis
- mendel didn’t know abt chromosomes or meiosis
dihybrid crosses
- examination of 2 separate traits in a single cross
- mendel produced true-breeding lines for 2 traits
- the F1 generation of a dihybrid cross shows only the dominant phenotypes for each trait
- allow F1 to self-fertilize to produce F2
polygenic inheritance
more than one gene can affect a single trait
(ex. 4 genes are involved in determining eye color)
pleiotropy
a single gene can affect more than one trait
(ex. cystic fibrosis)
phosphodiester bond
- bond between adjacent nucleotides
- formed between the phosphate group of 1 nucleotide and the 3’ OH of the next nucleotide
- the chain of nucleotides has a 5’ to 3’ orientation
central dogma
- francis crick
- information only flows from:
DNA –> RNA –> protein - transcription = DNA –> RNA
- translation: RNA –> protein
- retroviruses violate this order using reverse transcriptase to convert their RNA genome into DNA (ex. HIV)
gel electrophoresis
- separate DNA fragments by size
- submersed in buffer that can carry current
- negatively-charged DNA migrates towards the positive pole
- larger fragments move slower, smaller move faster
polymerase chain reaction
- allows the amplification of a small DNA fragment using primers that flank the region
Each PCR cycle involves three steps:
1. denaturation (high temperature)
2. annealing of primers (low temperature)
3. DNA synthesis (intermediate temperature)
quantitative RT-PCR
- reverse transcription quantitative PCR involves isolating mRNA, converting to cDNA using RT, then using PCR to amplify specific cDNAs
- amount of DNA produced can be measured in real time by the PCR machine
- can be found with DNA-binding dyes and probes
genetic engineering
- expressions vectors contain the sequences necessary to express inserted DNA in a specific cell type
- transgenic animals contain genes that have been inserted without the use of conventional breeding
(mouse eyeless gene worked to organize eye formation in Drosophila
CRISPR/Cas9 system
- a guide RNA targets Cas9 to a gene that matches the guide RNA sequence
- Cas9 can cut the DNA with which it is associated
- DNA can be repaired: double-stranded DNA containing a mutation can be provided to replace normal gene sequence
- Cas9 can also be targeted to activate or repress gene expression
gene therapy
- adding a functional copy of a gene to correct a hereditary disorder
- severe combined immunodeficiency disease (SCID) illustrates both the potential and the problems
(15 treated successfully, 3 developed leukemia)
knockout and transgenic organisms
- transgenic organisms are all or part transformed cells
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unifying themes in biology
cell theory
- all organisms are composed of cells
- cells are life’s basic units
- all cells come from preexisting cells
unifying themes in biology
molecular basis of inheritance
- deoxyribonucleic acid (DNA)
- sequence of 4 nucleotides encode cell’s info
- gene: discrete unit of info
- genome: entire set of DNA instructions
- continuity of life depends on faithful copying of DNA into daughter cells
what are the four components of the cellular membrane?
1.phospholipid bilayer
2.interior protein network
3.transmembrane proteins
4.cell surface markers.
define symporters and antiporters
symporters: a membrane transport protein that facilitates the movement of two different molecules across the cell membrane in the same direction.
antiporters: ^ different directions
