Gen Bio Exam 1

scientific method

observation, hypothesis, experiment, research, analyze, conclude

characteristics of living species

reproduction, heredity, homeostasis

ionic bonds

oppositely charged atoms with different electronegativities are electrostatically attracted to each other

covalent bond

sharing of an electron pair between two atoms

hydrogen bonds

hydrogen atom bonds to a strongly electronegative atom

weakest to strongest atoms

hydrogen, covalent, ionic

electronegativity scale

increase from left to right across the periodic table, decrease from top to bottom within a group

hydroxyl

carboxyl

phosphate

amino

methyl

sulfhydryl

polar covalent bond

covalent bond that occurs when atoms with different electronegativities share electrons unequally

which atom has a partial charge in a polar covalent bond

the atom with the lesser electronegativity

polar molecules interactions with water

molecules with partial or full charges, interact with water's dipoles and dissolve in it

nonpolar molecules interactions with water

don't interact well with water and can't form hydrogen bonds with water

general structure of an amino acid

a central carbon atom bonded to a hydrogen atom, an amino group, a carboxyl group and an organic side chain

side chains in amino acids

polar amino acids have side chains that interact with water, while nonpolar amino acids do not

polypeptide chains 3D folding near water

protein folding; polar amino acid side chains gather on the outside to interact with water, while nonpolar amino acid side chains form a tightly packed hydrophobic core

phospholipids

they have a polar head which is hydrophilic and two non-polar tails made of fatty acids which are hydrophobic

phospholipid bilayers

formed by two layers of phospholipids coming together, with the hydrophilic heads facing outward and the hydrophobic tails facing inward

membrane proteins

functions include communication, cell signaling, cell division, transport, adhesion

integral membrane proteins

located directly within the lipid bilayer, such as receptors and ion channels

peripheral membrane proteins

not directly located in the lipid bilayer but associated with the membrane indirectly, generally by interactions with integral membrane proteins

prokaryotic cells

absence of a nucleus, organelles, or a cytoskeleton.

eukaryotic cells

possesses a clearly defined nucleus and membrane-bound organelles

plasma membrane functions

protects the cell, regulates the transport of materials, provides structural support, and allows interaction with other cells through its proteins

plasma membrane makeup

semipermeable membrane that separates the inside of a cell from its external environment, mainly made up of the phospholipid bilayer

structure of nucleotides

consists of a nitrogenous base, a five carbon sugar, and a phosphate group.

structure of DNA

“backbone” made of alternating sugar and phosphate groups, the inside is made up of nucleotide bases and connected by hydrogen bonds between.

double stranded DNA molecule replication template

ensures that each dividing cell receives an identical DNA copy, each strand from the parent dictates which strand it will be on in each new daughter strand

DNA vs RNA

DNA is double-stranded while RNA is usually single-stranded. Sugar in DNA is deoxyribose, where RNA contains ribose. DNA uses the base of thymine whereas RNA uses uracil.

mRNA

messenger RNA; carries the protein blueprint

tRNA

transfer RNA; carries amino acids

rRNA

ribosomal RNA; makes up ribosomes

RNA

ribonucleic acid; carries DNA’s genetic info to ribosomes, binds to DNA through complementary base pairing

nucleus

double membrane-bound organelle that stores, retrieves, and duplicates genetic information

mitochondrion

organelle that constantly undergoes fission and fusion; energy-associated; “powerhouse of the cell”

cell wall

outermost layer of the eukaryotic cell; protects plasma membrane

cytoskeleton

network of interlinking protein filaments, aids in cell shape, organization, and movement

lysosome

the cell’s “garbage disposal”, breakdown of proteins

ribosomes

present in eukaryotic cells for protein synthesis

rough endoplasmic reticulum

covered in ribosomes on its surface, produces proteins which are folded

smooth endoplasmic reticulum

stores lipids and steroids

exon

coding sequences

intron

noncoding sequences

promoter

DNA sequence where proteins bind to initiate transcription

transcription

the process of making an RNA copy of a gene's DNA sequence.

translation

the sequencing of a mRNA molecule to a sequence of amino acids