CELLS Flashcards
what allowed the spontaneous abiotic synthesis of organisms?
conditions of early Earth
what are possible cellular precursors?
protobionts and RNA genesis
- are collections of abiotically synthesized organic compounds
- formed spontaneously as the precursors of cells
protobionts
cell structure is mainly composed of?
- cell membrane
- membrane proteins
- cytoplasm
- cytoskeleton
- ribosomes
- cholesterol
include multicellular plants and animals and some unicellular protists. Their cells contain membrane-bound organelles?
eukaryotes
membrane-bound organelles of multicellular organisms?
- nucleus
- mitochondria
- smooth/rough endoplasmic reticulum
- golgi apparatus
- vesicles
- lysosomes
additional components for plant cells?
- chloroplasts
- vacuole
- cell wall
simplest unicellular organisms and earliest cells to evolve?
prokaryotes
major differences of prokaryotes and eukaryotes?
- genetic material floats in the cytoplasm
- there are no membrane-bound organelles
unbounded but concentrated region for genetic material in prokaryotes?
nucleoid
cell transport has two mechanisms which are ?
active and passive
types of passive mechanisms?
- diffusion
- facilitated diffusion
molecules move freely across a membrane to balance a concentration gradient, from high to low concentration.
diffusion
diffusion of water
osmosis
molecules cross an impermeable or semi-impermeable membrane down their concentration gradient but must do so via special channels?
facilitated diffusion
types of active mechanisms?
- active transport
- endocytosis
- exocytosis
is the transport of molecules from low to high concentrations across a membrane using energy-dependent transport protein?
active transport
the enveloping of an exterior substance within a membranus vesicle for admission to the cell interior?
endocytosis
2 types of endocytosis
pinocytosis & phagocytosis
endocytosis of dissolved liquid molecules
pinocytosis
endocytosis of undissolved solid matter
phagocytosis
the extrusion of material from a cell by discharge vesicles at the cell surface?
exocytosis
is the cellular process of oxidizing glucose to obtain energy in the form of adenosine triphosphate (ATP) ?
cellular respiration
is the oldest metabolic pathway, used by all cells, and a precursor to both aerobic and anaerobic respiratory pathways.
glycolysis
where does glycolysis occur?
cytoplasm
what happens during glycolysis?
the six carbon-sugar glucose is degraded to form molecules of three-carbon pyruvate, resulting into two NADH and two net ATP.
chemical process by which molecules such as glucose are broken down anaerobically?
fermentation
three types of fermentation?
- homolactic
- alcoholic
- heterolactic
bacteria converts pyruvate into lactic acid
homolactic
yeast and bacteria convert pyruvate into ethanol and CO2
alcoholic
organisms produce lactic acid as well as other acids and alcohols
heterolactic
A chemical process in which oxygen is used to make energy from carbohydrates (sugars)?
aerobic respiration
stages of oxidative respiration?
- oxidation of pyruvate
- citric acid cycle (Krebs Cycle)
- chemiosmotic phosphorylation
- asexual reproduction by a separation of the body into two new bodies?
- is the method by which prokaryotes produce new individuals that are genetically identical to the parent organism?
binary fission
eukaryotic cell cycle involves?
- interphase
- M phase (mitosis)
- cytokinesis
phases of interphase?
- G1 phase
- S phase
- G2 phase
major period of cell growth?
G1 phase
during this period chromosome replication occurs producing sister chromatids connected by a centromere
S phase
the cells prepares for cell division during this period
G2 phase
the division of genetic material and cellular contents?
M phase
stages of mitosis
prophase
metaphase
anaphase
telophase
physical division of the cytoplasm into two daughter cells?
cytokinesis
produces for haploid nuclei called gametes from a single diploid cell
meiosis
cells divide in order to maintain _________________________________
surface-to-volume ratio
external signals that can regulate cell division
- growth factors
- density-dependent inhibition
- anchorage dependence
cells that ignore cell cycle regulations and divide unchecked
cancer cells
