intro to cell structure and function Flashcards
all living organisms are made of what?
cells
what are the simplest forms of living things?
unicellular
how to unicellular organisms multiply?
by dividing into two
cells are essentially small bags made of what?
bound by membrane containing a liquid made of water and a variety of chemicals, proteins, lipids, and carbohydrates
how have cells evolved over thousands of years?
natural selection- random genetic variation that’s passed on from one generation to the next and by selection of cells that can survive the environment in which they live
how is it believed life started on earth?
multiplication of a polynucleotide molecule in a rich “soup” of nucleotides which began to propagate and develop of 3D structure by bonding with nucleotides and other molecules and became more stable and able to carry information from one generation to the next while also having a specific function associated with their sequence and structure
what are the three key steps for the formation of cells?
- generation of self-replicating RNA
- production of proteins
- formation of the cell membrane
what is the original repositories of genetic information?
RNA moelcules
what became the keeper of the genetic code throughout the process of evolution?
DNA
what is the simplest cell form among today’s cells?
mycoplasma
what are mycoplasma?
small bacterium-like organisms that lead a parasitic life
how do mycoplasma synthesize 750 proteins essential for their survival?
structural proteins and enzymes synthesize small molecules inside the cell that are not available in the environment, which are capable of maintaining a suitable chemical environment within the cell by redistributing energy and organizing biochemical reactions in an optimal fashion.
what are the simplest organisms found in most environments and represent what?
bacteria
prokaryotes
what are the shapes of bacteria?
cocci and bacilli
how does bacteria differ from mycoplasma?
bacteria is larger and has a thick protective cell wall
what is the function of the cell membrane?
encloses nucleic acids, DNA, RNA, proteins, etc.
what is special about archaebacteria?
live in a variety of harsh environments such as ocean depths, salt brines, and hot acid springs. Some are even capable of converting carbon dioxide to methane
what is special about cyanobacteria?
obtain their nitrogen directly from atmospheric N2
how did anaerobic bacteria survive when the atmosphere became oxygen dense?
identifying niches that were low in oxygen or devoid of oxygen to support their existence
what is the most abundant cell type on earth?
bacteria
what organelles do eukaryotes have that prokaryotes don’t?
Nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus etc.
what are the two types of eukaryotic cells?
animal and plant
what is the difference between plant and animal cells?
animal: have a cell membrane and centrioles that play a vital role in cell division
plant: surrounded by cell walls with an underlying plasma membrane and they also have large vacuoles and specialized structures called chloroplasts that are essential for photosynthesis.
what are organisms of prokaryotes
bacteria and cyanobacteria
what are organisms of eukaryotes
Protists, fungi, plants and animals.
compare the metabolism of prokaryotes and eukaryotes
pro: anaerobic or aerobic
eu: aerobic
how do prokaryotes DNA differ from eukaryotes
pro: Circular DNA In cytoplasm
eu: Long stretches of DNA containing coding and non-coding regions, organized as chromatin and located in the nucleus
how do RNA and protein differ with prokaryotes and eukaryotes
pro: RNA and protein in the same compartment
eu: RNA synthesized in the nucleus, proteins in the cytoplasm
in eukaryotes, what is the cytoskeleton composed of? how is it different from prokaryotes?
protein filaments, cytoplasmic streaming, capable of endocytosis and exocytosis
pro: No cytoskeleton. No cytoplasmic streaming, endocytosis or exocytosis
how do prokaryotes divide vs eukaryotes?
pro: binary fission
eu: mitosis or meiosis
how is the nucleus separated from cytoplasm>
nuclear envelope made of two membranes
what is chromatin?
chromosomal DNA within the nucleus in a tightly wound form that uses histone proteins
what is the nucleolus?
dense body which is the site of RNA assembly
what are nuclear pores?
openings in the nuclear envelope that allow for exchange of contents between the cytosol and nucleus