Cell and Molecular Biology, Chapter 1
Nitrogen fixation
Conversion of nitrogen gas into reduced forms of nitrogen, such as ammonia than can be use by cells in the synthesis of nitrogen containing organic compounds including amino acids and nucleotides; some bacteria are capable
HeLa cells
Cultured tumor cells isolated from a cancer patient, Henrietta Lacks by George Get in 1951; first human cells for extended culturing
angstrom
one-tenth of a nanometer; atomic dimensions
Hematopoietic stem cells
produce blood cells in bone marrow
Complexity
prokaryotes are relatively simple; euks are more complex in structure and function
Capsid
protein coat + nucleic acid
Euk and pro similiarity:proteasomes
protein digesting structures of similar construction between archeabacteria and eukaryotes
Euk and pro similiarity: plasma membrane
similar construction
viral infection types: lytic infection
the virus that redirects the host into making more virus particles, the host cell LYSES and releases the viruses; "hijacking the cell'
Bacteriophage
bacterial viruses, most complex, most abundant biological entities on Earth; consists of a protein coat and nucleic acid; HIV
Cellular reproduction
euks divide by mitosis; proks divide by simple fission
Genetic material, form:
euks have many chromsomes made of both DNA and protein whereas prokaryotes have single, circuluar DNA
Genetic material, amount:
euks have much more genetic material than pros
Locomotion
euks use both cytoplasm movement, and cilia and flagella; pros have flagella but they differ in both form and mechanism
Cells evolve
evolved from precellular life form
Cyanobacteria
gave rise to green plants and an oxygen rich atmosphere
Evidence to support endosymbiont theory: 5
Organelles duplicate independently of nucleus
Evidence to support endosymbiont theory: 3
Organelles of euk cells contain their own DNA
Endosymbiont theory
Orgenelles in the eukaryotic cells (mitochondria and chloroplasts) evolved from smaller prokaryotic cells
Viroids
Pathogen, each consisting of a small, naked RNA molecule; cause disease by interfering with gene expression in host cells
Viruses
Pathogens; intracellular obligate parasites
Cells acquire and utilize energy
Photosynthesis provides fuel for all living organisms
Robustness
cells are hearty because they are protected from dangerous fluctuations in composition and behavior
Vorticella
have a contricle ribbon in the stalk and a large macronucleus that contains multiple copies of its genes
Cytosol
The soluble portion of the cytoplasm, which includes molecules and small particles, such as ribosomes, but not the organelles covered with membranes.
in vitro
in culture, outside the body
Euk and pro difference: cellulose
in plant cell walls
Metabolism
The sum total of the chemical reactions in a cell
Metagenome
The total gene content of the organisms present in an environment
Microbiome
Totality of the microbes, their genetic elements (genomes), an environmental interactions in a defined environment
Stem cells
Undifferentiated cells capable of self-renewal and differentiation
Virion
Virus particle outside the host cell
nucleus
a region bounded by a complex membranous structure called the nuclear envelope
Cells are capable of self-regulation
in the case of the sea urchin, half the cells were separated in early development and developed in to a whole sea urchin, rather than half
Robert Hooke
invented the microscope, first discovered cells in the mid 1600s.
neural stem cells
may be used to treat neurodegenerative disorders
Euk and pro difference: specialized organelles for aerobic respiration and photosynthesis
mitochondria and chloroplasts
Euk and pro difference: complex chromosome composed of...
...DNA and associated proteins that are capable of compacting into mitotic structures
Cells reproduce and each daughter cells receives...
...a complete set of genetic instructions
Feature found in euk and not pro: division of...
...cells into nucleus and cytoplasm, separated by a nuclear envelope containing complex pore structures
Euk and pro difference: complex flagella and...
...cilia
Viral specificity for a certain host is...
...determined by the virus' surface proteins; only infect certain types of cells/organisms
Multicellular eukaryotes have different cells types for..
...different fuctions
Euk and pro difference: presence of two copies of genes per cell...
...diploidy, one from each parent
Recent evidence indicates that pros are more....
...diverse and numerous than previous thought
Cells can grow and reproduce in culture for...
...extended periods; cultured cells are an essential tool for cell biologists
Based on whole genomes, many organisms appear to be...
...genetic mosaics
Cellular processes are...
...highly regulated
Euk and pro difference: Sexual reproduction requiring...
...meiosis and fertilization
Animal cells derive energy from the products of...
...photosynthesis, mainly in the form of glucose; cell can convert glucose into ATP- a substance with readily available energy
Euk and pro similiarity: inserting membrane...
...proteins
Euk and pro difference: cell division using a microtubule-containing spindle that...
...separates chromosomes
Cells from different speices...
...share similar structure, composition, and metabolic features that have been conserved throughout evolution
Viruses have surface proteins...
...that bind to the surface of the host cell
Euk and pro difference: ability to ingest...
..particulate material by enclosure within plasma membrane vesicles- phagocytosis
Pros are identified and classified on the basis of...
..specific DNA sequences
Cell size is limited by
1. volume of cytoplasm that can be supported by the genes in the nucleus 2. by the volume of the cytoplasm that can be supported by exchange of nutrients 3. by the distance over which substances can efficiently travel through the cytoplasm via diffusion
nucleoid
A dense region of DNA in a prokaryotic cell.
Organelles
A tiny cell structure that carries out a specific function within the cell.
Evidence to support endosymbiont theory: 1
Absence of eukaryote species with organelles in an intermediate stage of evolution
Prokaryotes
All bacteria, arose 3.7 billion years ago
Based on nucleotide sequences of single genes, Woese proposed three major cell lineages:
Bacteria: include gram +, gram =, and cyanobacteria Archaea: include halophiles, thermophiles, methanogens, and acidophiles Eucarya: include plants, animals, fungi, and protists
Cell biology is reductionist
Based on the premise that studying the parts of the whole can explain the character of the whole
Euk and pro similiarity: similar mechanism for photosynthesis
Between cyanobacteria and green plants
Adult stem cells
Can be used to replace dmaged or diseased adult tissue
Cells are able to respond to stimuli
Cells are covered with receptors that interact with substances in the environment
Turnover in a cell
Cells expend an enormous amount of energy breaking down and rebuilding the macromolecules and organelles of which they are made; maintains integrity and enables cell to respond to changing conditions
Model organisms
E. coli, saccharomyces, arabidopsis, c, elegans, drosophila, mouse
Euk and pro similiarity: genetic information
Encoded in DNA using identical genetic code
Cytoplasm
Euks have membrane-bound organelles and complex cytoskeletal proteins; both have ribosomes but differ in size
Most complex cells
Found in single celled protists; vorticella
Cells posses a genetic program and the means to use it
Genes encode information to build each cell, and the organism, for cellular reproduction, activity and structure
Viral structure
Genetic material and can be single-stranded DNA or RNA; protein capsid surrounds the genetic material; lipid envelope may surround the capsid in some viruses
Euk and pro similiarity: share metabolic pathways
Glycolysis and TCA cycle
Synthetic biology
Goal is to develop novel life forms, using existing organisms as a starting point, that have unique value in medicine and industry, or in cleaning up the environment
Embryonic stem cells
Have greater potential for differentiation (pluripotent) than adult stem cells; must be differentiated in vitro; use of these cells involves ethical considerations
Eukaryotic cells
Include protists, fungi, plants, and animals
Prokaryotic cells, domain bacteria
Include the smallest known cells: mycoplasma, cyanobacteria: photosynthetic bacteria
Euk and pro difference: Complex membranous cytoplasmic organelles
Includes Er, golgi complex, lysosomes, endosomes, peroxisomes, and glyoxisomes
Induced pluripotent cells have been demostrated in culture
Involves reprogramming a fully differentiated cell into a pluripotent stem cell; cells have been used to correct certain disease conditions in experimental animals; could have significant applications
LUCA
Last universal common ancestor
Euk and pro similiarity: similiar apparatus for conservation of chemical energy as ATP
Located in the plasma membrane and pros and the mitochondrial membrane of euks
Evidence to support endosymbiont theory: 2
Many symbiotic relations are known among different organisms
Cells engage in mechanical activities
Materials are transported, structures are assembled; motor proteins
Prokaryotic cells, domain archaea
Methanogens, halophiles, acidophiles, and thermophiles
Euk and pro difference: complex cytoskeletal system
Microfilaments, intermediate filaments and microtubules and associated motor proteins
Cells carry out a variety of chemical reactions
Miniaturized chemical plants; capable of hundreds of different reactions; require enzymes
Life
Most basic property of cells
Evidence to support endosymbiont theory: 4
Nucelotide sequences or rRNAs from euk organelles resembled that of prokaryotes
Synthetic biology tool box
Nucleic acids, proteins, and lipids
Differentiation
Occurs during embryonic development in other multicelluar organisms; numberes and arrangements of organelles relate to the function of the cell; despite differentiation, cells have many features in common
The origin of eukaryotic cells
Prokaryotic cells arose first and gave rise to eukaryotic cells; endosymbiont theory
Genetic material, packaging:
Proks have a nucleoid region whereas euks have a membrane-bound nucleus
Euk and pro difference: presence of three different RNA synthesing enzymes
RNA polymerase
Anton von Leeuwenhoek
Refined the microscope, used a single lens microscope; viewed pond water
Cell replacement therapy
Remove somatic cells from patient; fuse somatic cell with enucleated oocyte; allow to develop to blastocyst; grow embryonic stem cells in culture; induce ES cells to differentiate; transplant required differentiated cells back into patient
Lateral gene transfer
Results in organisms with both parental DNA and DNA from other organisms in the environment; bacteria and eucarya show evidence of LGT in their genomes
Tobacco mosaic virus
Rod shaped particle consisting of a single molecule of RNA surrounded by a helical shell composed of protein subunits
Cell theory
Schlieden, Schwann, and Virchow All organisms are composed of one or more cell The cell is the structural unit of life Cells arise from pre-existing cells by division
Chromatin
Substance found in eukaryotic chromosomes that consists of DNA tightly coiled around histones
Provirus
The integrated viral DINA; every time it divides, the infected DNA divides too
viral infection types: integration
the virus integrates its DNA (called a provirus) into the host cell's chromosomes; infected how may behave normally until it is activated, leading to lysis; host may give rise to viral progeny by budding; host may become malignant
Euk and pro similiarity: similiar mechanisms for
transcription and translation of genetic information including similar ribosomes