Human Bio Unit 2

Gene

Portion of DNA that holds instructions for making a protein

Gene expression

Gene is copied into mRNA and leaves the nucleus travelling to the endomembrane system in the cytoplasmRiboso

Protein synthesis

Ribosomes in the Rough ER read the instructions to make proteins from amino acids

Final Step

Newly synthesized proteins are to be modified, sorted and packaged by the Golgi Apparatus; Then shipped to vesicles where they will function

Covalent Bonds in DNA

Strong bonds that hold together the phosphate of one nucleotide to a sugar in the next nucleotide within the backbone of the DNA molecule

Hydrogen Bonds in DNA

Weak bonds that hold together bases of 2 nucleotides in the center of the DNA

Transcription

Process that occurs in the nucleus, where a gene region of 3’ is read → 5’ by RNA Polymerase while it synthesizes an mRNA transcript, building in the 5’ → 3’ direction using the order of bases in a gene region of DNA as a tempalte

Transcription Initiation

Open/euchromatin are activated by transcription factors to bind DNA and create a beacon to direct RNA Polymerase

Transcription Elongation

RNA Polymerase unwinds DNA and synthesizes mRNA determined by the complementary base pairings (Thymine turns to Adenine, Adenine turns to Uracil)

Transcription Termination

Stop codon causes RNA Polymerase to detach from DNA

Codons

Sets of 3 DNA bases that turn into amino acids

tRNA

Reads and translates mRNA into protein by matching anticodon region to codons

6 Properties of the genetic code

Triplet: Codons are in sets of 3 RNA base pairs

Non-Overlapping: mRNA bases are read only once

Degenerate: Multiple different codons can be translated into the same amino acid

Unambiguous: Each codon is always translated into the same 1 amino acid

Punctuated: Start Codon (AUG) is at the beginning of every organism and only the 3 stop codons are at the end of the amino acid chain

Universal: The same codons translate to the same amino acids in EVERY organism

rRNA

Facilitates the reading and binding of tRNA to mRNA; Catalyzes the bond between the growing protein chain & the new amino acids brought in by a tRNA

Silent Mutation

Codon changes but the amino acid does not change because of the degenerate property (UUU changes to UUC but they’re both the same A.A)

Missense-Conservative Mutation

Codon changes so amino acid changes but the new amino acid has the same molecular characteristic (Original chain and new chain both have a negative charge)

Missense-Non-Conservative Mutation

Codon changes so the A.A. changes and different molecular characteristics (Possible different 3D structure)

Nonsense Mutation

Codon changes to a stop codon, ending the translation early

Frameshift Mutation

All codons after insertion/deletion of mRNA base are changed

Semi-Conservative Replication

Uses old DNA molecule as a template to make a new strand and they stay together after replication to make a new molecule

Primase

Enzyme that creates RNA primers on region of DNA to create a double strand for the DNA Polymerase to bind to

Okazaki Fragments

Short fragments of DNA are made as DNA Polymerase moves away from the direction Helicase is opening the DNA

Helicase

Enzyme that unwinds the double-stranded DNA helix by breaking the hydrogen bonds

Telomeres

Regions on the ends of chromosomes that don’t code for proteins, once it’s gone then additional rounds of DNA replication will result in loss of important protein-coding regions resulting in cell death

Necrosis

Accidental damage caused by blunt trauma/infection: releases particles into the blood causing inflammation & calling over immune system to eat and recycle the dying cell

Apoptosis

Programmed cell death cycle cause by DNA damage; Caspases disassemble the proteins leading to degradation of the nucleus

Autophagy

Massive lysosome called a Phagosome slowly eats the cells from inside

Embryonic Stem Cells

Totipotent cells that can become any kind of cell in the body

Pluripotent Stem Cells

Can rise to one of the 3 germ layers but non every kind of cell

Multipotent Stem Cells

Germ layer stem cells that are able to become whatever cell type the germ layer needs

Ectoderm

Outermost part of the germ layer

Mesoderm

Middle part of the germ layer

Endoderm

Innermost part of the germ layer

Adult Stem Cells

Multipotent cells that can become a small subset of cells in the human body

Somatic Cells

Non potent cells that have a specific cell identity and do not reenter the cell cycle

2 Factors That Determine Gene Expression

Chromatin structure and transcription factors

Single Layer Epithelial Tissue

Specialized tissue for diffusion of nutrients/gases/toxins/water/ions

Multilayered Epithelial Tissue

Specialized tissue for protection and barrier function

Extracellular Matrix

Connects tissue and acts as a scaffold for cells of an organ and facilitate cell signaling/nutrient distribution

Fibroblasts

Cells of the ECM that secrete proteins that make up the ECM web-like tissue

Voluntary

Skeletal muscles that you move by thinking about it

Involuntary

Muscles that move without thought and can’t be controlled by thought, smooth & cardiac muscle for example

Nervous Tissue

Sends/receives signals throughout the body; can sense the environment; tells muscles to move; integrates information into a response

Pancreas

Enzymes and hormones that are released by this

Lipase

Enzyme that breaks down fats into small fatty acids and glycerol

Amylase

Breaks down carbohydrates into sugar monomers (glucose)

Protease

Enyzme that breaks fown proteins into amino acid monomers

Trypsin

Hormone that activates pancreas digestive enzymes in duodenum & protein digestion into amino acid monomers

Insulin

Hormone that triggers the liver to store glucose from the blood in large carbohydrate molecules called glycogen

Glucagon

Hormone that triggers the liver to release glucose from glycogen into the blood

Gastrin

Hormone that triggers the release of gastric juices such as pepsin, HCL, bicarbonate and mucus

Active transport

Amino acids move across the intestinal epithelia into the blood via

Bile Salts

Hydrophobic and hydrophilic to emulsify fats and mix with aqueous digestive juice

Plasma

Fluid that all the blood cells move around in, mainly water; carries proteins/salts/ions/some O2 and most CO2

White Blood Cells

Immune system cells that ride around blood vessels to see if any repair or help vs pathogens

Platelets

Cell fragments to help with clotting if there is a rupture of a blood vessel

Red Blood Cells

Carries most oxygen and so CO2 with the help of hemoglobin proteins