CHAP 4 - The Cellular Level of Organization

Cell

Basic structural and functional unit of the body

Cell membrane

Thin outer boundary of the cell that controls what enters and leaves

Intracellular fluid (ICF)

Fluid inside cells

Extracellular fluid (ECF)

Fluid outside cells

Phospholipid

Lipid made of a phosphate head and fatty acid tails

Amphipathic

Having both hydrophilic and hydrophobic regions

Hydrophilic

Attracted to water

Hydrophobic

Repelled by water

Phosphate head

Hydrophilic part of a phospholipid

Fatty acid tails

Hydrophobic parts of a phospholipid

Phospholipid bilayer

Double layer of phospholipids forming the cell membrane

Membrane protein

Protein located in or attached to the cell membrane

Transmembrane protein

Protein thats across the cell membrane

Peripheral protein

Protein attached to the surface of the cell membrane

Glycoprotein

Protein with a carbohydrate attached

Glycocalyx

Carbohydrate-rich layer outside of the cell membrane

Selectively permeable

Allows some substances to cross while restricting others

Concentration gradient

Difference in concentration between two areas

Passive transport

Movement across the membrane without cellular energy

Active transport

Movement across the membrane using cellular energy

Simple diffusion

Movement of substances from higher to lower concentration through the membrane

Facilitated diffusion

Movement from higher to lower concentration through a membrane protein

Osmosis

Movement of water across a selectively permeable membrane

Hypotonic solution

Solution with lower solute concentration than the cell

Hypertonic solution

Solution with higher solute concentration than the cell

Isotonic solution

Solution with equal solute concentration to the cell

Hyperosmotic

Having a higher concentration of dissolved particles

Hypoosmotic

Having a lower concentration of dissolved particles

Isosmotic

Having equal concentrations of dissolved particles

Tonicity

Ability of a solution to cause a cell to gain or lose water

Primary active transport

Transport that uses ATP to move substances against their concentration gradient

Secondary active transport

Transport that uses the energy stored in an ion concentration gradient

Sodium-potassium pump

Protein that uses ATP to move sodium out of the cell and potassium into the cell

Symporter

Transport protein that moves two substances in the same direction

Antiporter

Transport protein that moves two substances in opposite directions

Endocytosis

Process of bringing substances into the cell by forming a vesicle

Exocytosis

Process of releasing substances from the cell by vesicles fusing with the cell membrane

Receptor-mediated endocytosis

Endocytosis that uses specific membrane receptors to bring substances into the cell

Phagocytosis

Endocytosis of large particles or cells

Pinocytosis

Endocytosis of extracellular fluid and small dissolved substances

Cytoplasm

All cell contents between the cell membrane and nucleus

Cytosol

Fluid portion of the cytoplasm

Organelle

Specialized structure inside a cell that performs a specific function

Endoplasmic reticulum (ER)

Membrane system that produces and transports substances

Rough ER

ER covered with ribosomes that produces proteins

Smooth ER

ER without ribosomes that produces lipids

Golgi apparatus

Organelle that modifies, sorts and packages proteins and lipids

Cis-face

Receiving side of the Golgi apparatus

Trans-face

Shipping side of the Golgi apparatus

Lysosome (cleanup crew)

Organelle that contains enzymes that breaks wastes/materials down

Peroxisome (detox)

Organelle that breaks down fatty acids and detoxifies harmful substances

Mitochondria

Organelles that produce most of the cell's ATP

Cristae

Folds of the inner mitochondrial membrane

Cytoskeleton (cells skeleton)

protein fibers that supports/structures the cell

Microtubules (cell highways - apart of the cyloskeleton)

Cytoskeletal fibers that support the cell, move materials, and separate chromosomes during cell division.

Intermediate filaments (cell’s strong ropes)

Strong protein fibers that support and strengthen the cell.

Microfilaments (movement)

Thin protein fibers that help the cell move and change shape.

Microvilli (vacuum)

increase surface area for absorption

Cilia (sweep)

move substances across the cell surface

Flagella (flag waving)

used by cells to move through liquid

Nucleus

Organelle that contains DNA and controls many cell activities

Nuclear envelope

Double membrane surrounding the nucleus

Nuclear pores

holes in the nuclear envelope that regulates movement in and out of the nucleus

Nucleolus (ribosome factory)

produces and assembles the cell’s ribosomes

DNA

carries genetic information

mRNA (message)

carries genetic instructions from DNA to a ribosome

tRNA (transport)

transports amino acids to the ribosome

rRNA (ribosomes)

Makes up ribosome and proteins

Histone (spool 🧵)

Protein that DNA wraps around to pack DNA

Chromatin (loose DNA)

DNA and associated proteins in the nucleus

Chromosome

A tightly packed structure of DNA that contains genes.

Gene

part of DNA that contains instructions for a functional product

Protein synthesis

Process of making proteins using genetic information

Transcription

process of copying DNA into mRNA.

RNA polymerase

Enzyme that builds an RNA strand during transcription

Polypeptide

Chain of amino acids

Translation

Process of using mRNA instructions to build a polypeptide

Ribosome

Structure that reads mRNA and assembles amino acids into a polypeptide

Peptide bond

Bond connecting amino acids in a protein

Cell cycle

cycles where a cell grows and divides

G1 phase (grow)

Phase of cell growth

S phase (replicate/copy DNA)

Phase when DNA is replicated

G2 phase (division)

Phase when cells prepares for division

Somatic cell

Any body cell other than a reproductive cell

Diploid

Having two sets of chromosomes

Haploid

Having one set of chromosomes

Meiosis

Cell division that produces reproductive cells with half the chromosome number

Helicase

Enzyme that separates the two strands of DNA

DNA replication

Process of copying DNA before cell division

DNA polymerase

Enzyme that adds nucleotides to build a new DNA strand

Mitosis

Division of the nucleus producing two genetically similar nuclei

Interphase

in between divisons

Prophase

chromosomes condense and the spindle begins forming

Metaphase

chromosomes line up at the middle of the cell

Anaphase

sister chromatids separate and move to opposite sides

Telophase

new nuclei form around the separated chromosomes

Cytokinesis

Division of the cytoplasm into two daughter cells

Cleavage furrow

dent that forms as an animal cell divides during cytokinesis

Contact inhibition

Cells stop dividing when they touch nearby cells.

Cellular differentiation

Process by which cells become specialized (made for a specific job)