mod 1 Flashcards
Cell
Simplest entity that can exist as an independent of life
generally cells have a discrete boundary that seperates the interior of the cell from its external envrinmental; they contain a stable blueprint of info in molecular form; and they have abaility to harness materials and energy from the envirnment
Cell membrane
or plasma memebrane, seperates the living material within the cell from the nonliving envirnment around it
All cells require sustained contributions from their surroundings, both simple ions and the building blocks required to manufacture macromolecules
cells alos release waste prodcts into envirnment - they control movement of materials in and out of cell
nucleus
Houses the cells DNA
nuclear membrane ontrols movement of molecules in and out of it
Cytosplasm
the space outside of nucleus and inside the cell membrane
Prokaryotes and Euakryotes
Prokaryotes are without nucleus and eukaryotes are with
Success of prokaryotes deepdns on their small size, their ability to reproduce rapidly and ability to obtaine enrgry and nutrients from diverse sources - Most prokaryotes are single celled
Eukaryotes evolved after - in multicellular organsims, cells are specialized to perform diff functions
Domains of life
Bacteria, archea, and eukarya
Bacteria and archea are single celled micororganisms that lack nucleus and are prokarotes
eukarya have a nucelus and are eukaryotic
Archea floruish under hostile conditions
Nucleic acids
After membranes, the second essntial feature of teh cell is ability to store and transmit info
in all living organsims, the info archive is a molecule known as deoxyribonuclic acid or DNA
Takes form of double helix with each stand made up of varying sequences of 4 diff molecules connected end to end - they encode the cellular info
info in DNA is used as template for synthesis of ribonuclic acid or RNA - ribosomes read RNA to build proteins
Proteins are molecules that provide structure and do much of the work of the cell
synthesis of RNA from DNa is transcription - syntehsis of proteins from RNA is translation - going from DNA to RNA to protein is central dogma of moleculear bio - it describes teh flow of inof in cell
Gene: the DNa sequence that corresponds to a functional product like a protein
DNA is also easily replicated - DNA replication allows genetic info to be passed from cell to cell or organism to progeny - each strand of helix serves as template for new strand - errors in DNA replication lead to changes in the DNA sequence known as mutation
Metabolism
3rd key feature of cells is ability to harness eenrgy from teh envirnment
Organsims acquire energy from two sources - sun adn chem compounds
Metabolsim describes chem rxns by which cells conevrt energy from one form to another and build or break dwon molecules
metabolic rxns needed to sustain life
Organisms use chem rxns to break down molecules in process reelaing energy that is stored in chem form called adenosine triphophate or ATP - energy currentcy of the cell
Cell theory
Cells differ in size and shape but they share many features
There is no life without cells and the cell is the basic unit of life
Cell theroy:
- all organisms are made up of cells
- the cell is the fundemntal unit of life
- cells come from preexisting cells
All organisms are made up of cells - some unicellular others multicellular - in multicellular the cells are specilized to carry out diff functions
The cell is the fundemental unit of life - the cell is the simplest entity that we can define as living - ability to repoduce, respond to envirnment, harness energy, evolve etc. - cells are the smallest, most basic unit of life and theres not life without cells
Cells arise from prexisting cells through provess of cell division
Structure and function of cells
Centrals ideas of bio is that structure and function are related
Structure of cells will relate to their function
- ex. RBC has bioconve shape which allows it to pass through narrow blood vessels
Cells as prokaryotes or eukaryotes
Cells of projaryotes like bacteria and archea lack nucelus while the cells of eukaryotes have a nucelus - DNA can be housed in membrane bound nucleus or not
Prokaryotes were first forms of life - genetic material organized into circular chromsome - genetic material in region of cell called nuceloid - cell wall around cell membrane which keeps shape - some bacteria have flagella - small cells which gives high ratio of surface area to volume which allows it to absorb nutreints from envrinment
Eukaryotic cells are bigger - have an extensive internal array of membranes - membranes define compartments called orgnalles that divide cell contents into smaller spsces specialized for functions - organelles carry out diff functions important to cell
Nucleus is an organelle - houses DNA which is in multiple linear chromsomes - ncuelus allows for complex regulation of gene expression - transcription and translation seperated in space and time which can be regulated seperately unlike prokaryotes
