Cell Biology

Organizational hierarchy Organism Systems Organs Tissues Cells Organelle Molecules

• AKA Plasma membrane • Made of phospholipid bilayer • Some proteins included • Protects the cell • Selectively permeable

• Comprised of two parts • Cytosol – liquid • Organelles • Gives volume to the cell

• Flattened sac-like appearance • Modifying and packaging center • Prepares proteins for transport outside of the cell • Packages proteins in a vacuole • “Fed-Ex”

• Site of protein synthesis (creation) • Can be found free in the cytoplasm or bound to the rough endoplasmic reticulum

• Rough – contains ribosomes • Makes proteins for transport • Smooth – does not have ribosomes • Makes lipids and carbohydrates

• Powerhouse of the cell • Site of cellular respiration • Responsible for making ATP vis Krebs cycle • ATP is energy currency for cell

• “Brain” of the cell • Stores DNA • Makes RNA and ribosomes • Surrounded by nuclear membrane • Nuclear pores allow RNA to move in and out of nucleus

• Lysosome – site for waste disposal • “Garbage disposal” of the cell • Centriole – cylindrical structure used to make spindle fibers for cell replication • Cytoskeleton includes microtubules and microfilaments

• Deoxyribonucleic acid • Blueprint for organism • Double helix • Sugar-phosphate backbone • Rungs of nucleotide base pairs

– only 2 possible pairings * Thymine – Adenine * Cytosine – Guanine

• Occurs before cell division • Semi-conservative process • Splits the double helix down the middle -Each new strand is half of the old strand

• Ribonucleic Acid • Single-stranded molecule • Uses DNA as a template • Chargaff’s Rule changes for RNA • Uracil – Adenine • Cytosine – Guanine

Transcription, translation

When the information from DNA is made into a functional product

• DNA codes for RNA which codes for proteins • DNA has genes • Each gene codes for a protein or a regulating molecule

• Allows the DNA to be functional • All cells within an organism has the same DNA but they do not all look the same or act the same! • Gene expression allows cells to differentiate their roles

• Synthesis of mRNA from DNA • Occurs in the nucleus -Usually one gene at a time • Controlled by segments of DNA called transcription factors - Can turn a gene on or off -Can increase or decrease how often that gene is expressed

• The synthesis of protein from mRNA -Occurs at a ribosome in the cytoplasm or RER • mRNA contains codons -3-base segments • tRNA contains the anticodon that matches the codon - Associated with specific amino acids -Amino acids are the building blocks of proteins

Prokaryotic Eukaryotic

• Small, single-celled organisms • No nucleus • DNA is circular • Lacks membrane-bound organelles • Usually have cell wall

• Larger cells • Nucleus and linear chromosomal DNA • Membrane-bound organelles • Cell wall depends on type • Animal cells – no wall • Plant, fungi, protozoa cells – wall

Archaea Bacteria Eukaryotic

• Prokaryotic cell • Extremophile