BIO 183- Cellular and Molecular Biology

Created for BIO 183 at NC State

Cell

Smallest fundamental unit of life

Molecule

Group of 2 or more atoms held together via chemical bonds, the smallest unit of a substance that still has the characteristics of that substance

Hypothesis

Proposed explanation for a natural phenomenon or observation that is to be tested during an experiment

Theory

An explanation of a natural phenomenon that has been supported by many experiments over a long period of time ex. thermodynamics, evolution

Prediction

An exact proposed outcome of one’s experiment

Falsifiable

Refers to the fact that a hypothesis cannot be proven, only supported (or the opposite)

Baseline

Starting measurement in an experiment

Control

A group of individuals in an experiment not receiving the independent variable

Deoxyribonucleic Acid (DNA)

Fundamental molecule of life that contains genetic information

Carbohydrates, lipids, proteins, nucleic acids

Four classes of organic molecules

Covalent Bond

A chemical bond in which two atoms share electrons

Atom

Smallest unit of a chemical element

Electron

Negatively charged particles that move around a nucleus within ‘clouds’ called orbitals

2n²

Formula for remembering how many electrons can go in each shell of an atom

Carbon

Foundational element of organic molecules that, by definition, makes it organic

Gene

A section of DNA that codes for a specific trait/action

Chromosome

What DNA condenses into to allow for cell replication

Intron

Repetitive sections of DNA that are condensed and do not code

Exon

Non-repetitive section of DNA that ‘exit’ the nucleus to code for RNA

Telomere

Specialized structures found in eukaryotes at the end of chromosomes that protect them, provide stability, and oversee how genes are expressed. Deteriorate (get shorter) with repeated replication.

Phosphate group, 5-carbon deoxyribose sugar, nitrogenous base

Three structures that make up nucleotides

Nucleotide

‘Building blocks’ of DNA, string together to form nucleic acid macromolecules, specifically DNA

OH

Chemical formula for a hydroxyl group

Adenine, thymine, cytosine, and guanine

The four nitrogenous bases found in DNA

The Central Dogma

Foundational concept in biology that describes how DNA codes for RNA which then codes for proteins

Structural, transport, enzymatic

Three main roles of proteins

Hydrogen Bond

When the hydrogen of one molecule chemically bonds to an electronegative atom of another molecule, creating a slightly negative charge

Daughter Cells

The result of cell replication, there are two and they are identical to both each other and the parent cell

Gene Expression

The concept that explains why cells can all have the same DNA in them, but be very different based on which genes are active

DNA Replication

The process in which a cell’s DNA is copied using a variety of enzymes to allow for cell division

Antiparallel

The term that refers to the fact that DNA strands run next to each other in opposite directions

Semiconservative

The term that refers to the fact that one strand in replicated DNA is from the parent strand, and one strand is new

-ase

The suffix that indicates it’s an enzyme

Helicase

Enzyme that opens up the helix to start DNA replication

Primase

Enzyme that makes primers, pieces of RNA that allow for the start of DNA replication and will later be removed

DNA Polymerase

Enzyme that creates a new strand of DNA by laying down complementary base pair nucleotides. Able to self-correct mistakes.

Ligase

Enzyme that fills in the gaps in replicated DNA left by RNA primer

Replication Fork

Refers to the spot in which a DNA strand is being unraveled for replication

Leading Strand

The strand of DNA that is read straight across and built continuously

Lagging Strand

The strand of DNA that is read and built discontinuously in pieces called Okazaki fragments

Okazaki Fragments

The name of the pieces created from replicating the lagging strand of DNA

Telomerase

Enzyme that adds its own ‘buffer’ to extend the 3’ ends of DN to keep them from losing important genetic information. More activity in cancer cells.

Surface area to volume ratio, diffusion distances, nuclear control, rate of transport

The four reasons why it is evolutionarily favorable for cells to be small in size

Diffusion

Movement of substances from high to low concentration. Doesn’t require energy, but can only happen over short distances

Dynamic Equilibrium

Same concentrations of a substance on both sides of a membrane, no gradient

Nuclear Control

How well a nucleus is able to maintain and regulate a cell, with smaller cells having more _____.

Neurons, some algal cells

Cells that have acquired adaptations that allow them to be exceptions to the small cell rule

Cytoplasmic Streaming

Evolutionary adaptation in cells in which organelles are always moving through the cytoplasm, making transport faster

Cytoplasm

Gel-like aquatic environment contained inside of a cell membrane. Proteins, ions, sugars, RNA, and the cell’s organelles can all be found here.

Membrane Bound Organelles

The main difference between prokaryotes and eukaryotes is that prokaryotes do not have ______.

Prokaryote

Single cells with no nucleus or membrane bound organelles ex. archaea, bacteria

Eukaryote

Cells with a nucleus and membrane bound organelles ex. amoeba

Organelle

Compartment within a cell that serves a specific function. The compartments create a specific environment in terms of pH, enzymes, etc. that allow it to perform its function.

Nucleus

Organelle that stores and protects genetic material and regulates gene expression

Mitochondria

Organelle that produces ATP through cellular respiration

Smooth Endoplasmic Reticulum

Organelle that synthesizes lipids and detoxifies

Rough Endoplasmic Reticulum

Organelle responsible for protein production. Covered in ribosomes that perform protein synthesis

Peroxisome

Organelle that oxidizes the cell to neutralize toxicity. Breaks down hydrogen peroxide into water and oxygen

Vesicle

The “vehicles” of the cell, responsible for material transport

Lysosome

Organelle that digests waste using enzymes

Golgi Body/Apparatus

Organelle that modifies, sorts, and packages proteins. Prepares for excretion from the cell by directing vesicles

Centrioles

Organelle that allows for cell replication by forming the spindle apparatus, which pull apart chromosomes in mitosis/meiosis

Chloroplast

Organelle in which photosynthesis occurs. Not found in animal cells

Vacuole

Organelle that acts as water storage. A large “central ____” exists in plants and gives them their turgidity

Turgidity

The force of water contained in vacuoles pushing against the walls of a cell. Allows plants to have structure. Wilting occurs when plants do not have this.

Lipid

A class of biological molecules characterized by being insoluble in water

Triglyceride

1 glyceride attached to 3 fatty acids

Hydrophobic

Describes when a molecule repels water and is generally nonpolar and insoluble in water. This describes the ‘head’ end of a phospholipid

Hydrophilic

Describes when a molecule interacts with water and is generally polar and water soluble. This describes the ‘tail’ end of a phospholipid

Phospholipid

Glycerol attached to 2 fatty acids and a phosphate group ‘head’

Unsaturated

The term for when lipids have 1+ double bonds in its fatty acid creating a ‘kink’. These lipids are not able to pack as tightly together, hence the name…

Saturated

The term for when lipids have only single bonds in its fatty acids and are able to pack more tightly together

Cholesterol

A kind of lipid often found embedded in plasma membranes of non-plant cells to preserve fluidity and produce hormones. Essential to functioning, but harmful to your health at high levels.

Phospholipid Bilayer

The structure that makes up many plasma membranes, composed of two rows of phospholipids pointed with their heads out in opposite directions

The Fluid Mosaic Model

Plasma membranes are fluid structures that contain more than just phospholipids, but also an array of proteins, carbohydrates, cholesterol, and more

Essential

The term for when a substance is needed for an organism to survive, but it is unable to produce it on its own and therefore must ingest it through its diet

Cofactor

A molecule (often lipid) that assists in completing the job of an enzyme

Mitosis

The process of nuclear cell division that occurs in between interphases

Animal Cytokinesis

The process in which animal cells contract microtubules to form a cleavage furrow that pinches off the cell membrane to complete cellular division

Centromere

The center part of a chromosome that holds the sister chromatids together

Chromatid

Two structures called ‘sister ___’ that together make up a chromosome

Kinetochore

The spot on a chromosome in which mitotic spindles attach

Microtubules

The small tube-like structures that make mitotic spindles

Prophase, Metaphase, Anaphase, Telophase

The four (main) stages of mitosis

Prophase

The phase of mitosis in which the nuclear envelope dissolves, DNA condenses into chromosomes, and spindle fibers are produced

Metaphase

The phase of mitosis in which chromosomes line up at the center of a cell at the equatorial plate and are then pulled apart by spindle fibers attached at the kinetochores

Anaphase

The phase of mitosis in which the cell begins to divide down the center and pull apart

Telophase

The phase of mitosis in which the nuclear envelope is rebuilt, chromosomes unravel into DNA, and spindle fibers break down. It occurs around the same time as cytokinesis

Cellular Divsion

The combined process of mitosis and cytokinesis that starts when cells are old, damaged, or more are needed for growth

Plant Cytokinesis

The process in which vesicles build up around the equatorial plate of a plant cell, forming a cell plate that becomes a new section of cell wall between two daughter cells, completing cellular division

Cleavage Furrow

The structure formed during animal cytokinesis when the microtubules contract and begin pulling the two daughter cells apart

Equatorial Plate

The center line of a cell that is the site of cytokinesis

G1, S, G2

Three subphases of interphase

Synthesis and DNA Replication

What the S phase of the cell cycle stands for and the process that occurs

G1

The subphase of interphase occurring right after mitosis in which a cell is metabolically active and producing organelles such as mitochondria to provide it with the size and energy to initiate the next phase

S

The subphase of interphase in which DNA replication occurs, preparing for cellular division

G2

The subphase of interphase right before mitosis in which the microtubules form to make the spindle fiber apparatus

Spindle Fiber Apparatus

The structure of interconnected microtubules formed during the G2 phase that allows the cell to divide

Cyclin

Chemical signal in the cell cycle that builds up in concentration until a threshold is reached, then the next phase of the cell cycle begins

Cyclin-Dependent Kinases (CDK)

A type of kinase that requires the presence of cyclin to be activated