Week 4 - A Tour Of The Cell Flashcards
Unified cell theory
All living things made of cells
Two types of cells
Prokaryotic and Eukaryotic
“Pro”-before, early, pre
“Kary”-nucleus (carries DNA)
Prokaryotic cells
Lack membrane bound organelles; Have a nucleoid instead of a nucleus
Domains Archaea and Bacteria are prokaryotic
Eukaryotic cells
Have membrane bound organelles and true nucleus (houses the genetic material)
“Eu”-good, true
“Kary”-carries DNA
Three domains of biology
Eukarya - plants, animals, fungi
Archaea
Bacteria
Organelle
Mini organ or structure within a cell
Organelle - “organs” of the “cell” –> organelle
Nucleus
Center of cell, holds genetic material and directs mfg of proteins.
Three main parts:
1) nuclear envelope / membrane
2) nucleolus (center of nucleus, makes ribosomes)
3) chromatin (houses chromosomes, genetic material, DNA)
Cytoplasm
Everything inside the cell between PM and nucleus including:
Cytosol, Organelles, Proteins, Chemicals
Cytosol
Fluid within the cell. Water based, gel-like substance. Part of the cytoplasm.
Nuclear envelope
Aka nuclear membrane
Functions: encases the nucleus; controls what comes in and out
Chromatin
Mass of DNA and the proteins that give it structure/organization
Chromosome
The long, discrete strands of DNA; smallest units of DNA
Nucleolus
Makes ribosomes; center of nucleus
Ribosomes
Organelle that makes proteins (protein synthesis)
Receive instructions from RNA
comprised of a small and large subunit that attach to mRNA in protein synthesis
Two types:
FREE RIBOSOMES - float around freely in the cytoplasm
BOUND RIBOSOMES - bound to the ER or nuclear envelope
Lysosomes
Organelles that break things down via hydrolysis using Digestive enzymes
Can break down food or damaged cell materials; Made by the Golgi apparatus/complex
Peroxisomes
Facilitate oxidation rxns by providing the needed enzymes
Break down toxic materials (like alcohol —> lots of peroxisomes in the liver!) and FAs
Why is it important for enzyme containing organelles like Lysosomes and Peroxisomes to be membrane-bound?
So the cell doesn’t digest itself!
Vacuoles
Large compartments with specific fxns in different organisms
Examples:
Food vacuoles - sacs of nutrients taken in to be digested by lysosomes
Contractile vacuoles - pump water out of cell in freshwater unicellular eukaryotes IOT maintain proper water/ion concentration
Central vacuole - common in mature plant cells; storage and cell growth
Endoplasmic reticulum - 2 types
Smooth ER - no ribosomes
Rough ER - embedded ribosomes on outer surface
All ER is continuous w/ nuclear membrane; Internal area is separate from cytosol and called ER lumen
Smooth ER functions
Makes lipids (incl. steroids) and carbs
Detox of drugs/poisons
Stores Ca ions
Rough ER functions
Creates proteins (ribosomes) to secrete from cell Makes membrane phospholipids for itself and rest of cell
Golgi apparatus/complex
Receives sorts and transports proteins - post office of the cell
Cis face receives vesicles; trans face sends them off (for transport)
May modify product (e.g. protein) before sending off
Receives transport vesicles from ER (e.g. containing proteins)
Endosymbiont Theory
explains origins of mitochondria and chloroplasts; Idea that they were once free but got absorbed by a eukaryote ancestor
mitochondria and chloroplasts: Have their own DNA Replicate their DNA autonomously Have their own ribosomes Approx same size as a bacterial cell
Mitochondria
perform cellular respiration; use O2 (aerobic) to obtain ATP (energy) from food to power cell.
