Human Anatomy and Physiology, Chapter 3, Cells

Plasma membrane

Wall separating cells' internal and external environments

Cytoplasm

Has all cellular contents between plasma membrane and nucleus

Cytosol

Liquid in the cytoplasm (intracellular fluid)

Organelles

Specialized parts of the cell that perform different functions within the cell

Nucleus

Largest organelle in the cell

Lipid bilayer

Two layers made up of three types of lipid molecules, phospholipids, cholesterol, and glycolipids

Integral proteins

Extends into or through the lipid bilayer

Peripheral proteins

Proteins loosely attached to the exterior or interior surface of the membrane

Selective permeability

The membrane’s ability to allow some substances through while denying others

Ion channels

Channels that allow certain ions into the cell

Carriers (transporters)

Membrane proteins that can change shape as they move substances from one side of the membrane to the other

Receptors

Recognizes and binds a certain molecule that governs some cellular function

Cell identity markers

Allow them to recognize similar cells to form tissue and respond to danger (glycoproteins and glycolipids)

Interstitial fluid

Fluid in between tissue cells

Blood plasma

ECF in blood vessels

Lymph

ECF in lymphatic vessels

Cerebrospinal fluid

ECF within and around the brain and spinal cord

Diffusion

Substances move through a passive process

Simple diffusion

Substances diffuse across a membrane through the lipid bilayer

Facilitated diffusion

Integral membrane protein assists a certain substance to move across the membrane

Osmosis

Movement of water molecules across a semipermeable membrane from an area of low solute concentration to an area of high solute concentration

Osmotic pressure

Pressure on the membrane by solutes that cannot enter the membrane

Isotonic solution

Solution where cells keep their shape

Hypotonic solution

Solution has a lower concentration of solutes than the red blood cell fluid does, causing water to rush into the cell

Hemolysis

Rupture of a red blood cell due to excess swelling

Hypertonic solution

Solution has a higher solute concentration than the cytosol inside the red blood cell does

Crenation

Shrinkage of a red blood cell

Pump

Uses ATP energy to move molecules against the concentration gradient

Sodium-potassium pump

Helps maintain a low concentration of sodium ions in the cytosol

Vesicle

Small round sac that forms around an existing membrane

Phagocytosis

Cell “eats” by surrounding and swallowing large particles

Psuedopods

Temporary “feet” pushed out by the cell to help move or eat surrounding particles

Bulk-phase endocytosis

“Cell drinking”, body cells take in solutes dissolved in ECF

Cytoskeleton

Network of three different protein filaments: microfilaments, intermediate filaments, and microtubules

Microfilaments

Thin protein fibers that provide mechanical supports, helps generate movement, and helps divide

Microvilli

Tiny finger-like projections that increase surface area and help with absorption

Intermediate filaments

Help hold organelles in place and help attach cells to one another

Microtubules

Long hollow tubes that help determine a cells shape and function

Centrosome

Area in a cell that organizes microtubules and helps during cell division by pulling chromosomes apart

Centrosome parts

Pair of centrioles and pericentriolar material

Cilia

Short, hairlike projections from a cells surface

Flagella

Long tail projecting the cell, like sperm tails

Ribosomes

Sites of protein synthesis

Endoplasmic reticulum

A network of folded membranes in the form of flattened sacs or tubules

Rough ER

Has ribosomes on its surface and helps makes proteins

Smooth ER

Has no ribosomes and helps make lipids and detoxifies the cell

Golgi complex

Modifies, sorts, and packages proteins and lipids

Lysosomes

Break down waste, old cell parts, and harmful material

Autophagy

Cell digests it’s damaged parts

Autolysis

Cell digests itself completely

Peroxisomes

Small cell organelles that break down toxic substances and help with metabolism of fats

Proteasomes

Protein complexes in a cell that break down damaged or unneeded proteins to be reused as amino acids

Mitochondria

“Powerhouse of the cell”, produces energy (ATP)

Outer mitochondrial membranes

Lets molecules in and out freely

Inner mitochondrial membranes

Where energy is made during cellular respiration

Mitochondrial matrix

Space inside the inner membrane

Nucleus

Cell’s control center that stores DNA and directs cell activities

Nuclear envelope

Double membrane surrounding nucleus and protecting DNA

Nuclear pores

Tiny openings in the envelope to let materials move in and out of the nucleus

Nucleoli

Small structures inside the nucleus that make ribosomes

Genes

Section of DNA that carry the instructions for making proteins

Chromosome

Tightly coiled packages of DNA

Chromatin

Loose threadlike form of DNA and proteins

Genome

The entire set of DNA in an organism

Base triplet

A sequence of three DNA bases

Codon

A sequence of three RNA bases

Transcription

Process where a gene in DNA is copied into mRNA

RNA polymerase

Catalyst to speed up DNA transcription

Promoter

Special DNA sequence at the start of a gene where RNA polymerase binds to begin transcription

mRNA (messenger RNA)

carries the instructions from DNA to the ribosomes

rRNA (ribosomal RNA)

Makes up the ribosome, where proteins are built

tRNA (transfer RNA)

Brings the correct amino acids to the ribosome to build the protein

Terminator

A DNA sequence that tells RNA polymerase to stop transcription

Translation

The process where the ribosome reads the mRNA code and uses tRNA to build a chain of amino acids

Anticodon

Three bases on a tRNA that pairs with the codon on an mRNA translation

Polyribosome

When many ribosomes attach to the same mRNA at once

Cell division

When cells reproduce themselves

Meiosis

Produces gametes (sperm and egg cells) with half the number of chromosomes

Somatic cells

All body cells except sperm and egg

Somatic cell division

The process (usually mitosis) where somatic cells make identical copies to grow or repair tissue

Cell cycle components

Interphase, Mitosis, Cytokinesis

Interphase

Cell grows and DNA is copied

Mitosis

Nucleus divides

Cytokinesis

Cytoplasm divides, making two identical cells

Prophase

Chromatin coils into visible chromosomes and mitotic spindle stars forming

Chromatids

identical halves of a duplicated chromosome

Mitotic spindle

A network of microtubules that pull chromatids apart during cell division

Metaphase

Stage of mitosis where chromosomes line up in the middle of the cell

Metaphase plate

imaginary line in the center where the chromosomes line up

Anaphase

Chromatids move to opposite sides

Telophase

Chomatids reach the poles and the nuclear envelope reforms

Cleavage furrow

Indentation that forms in the cell membrane during cytokinesis as the cell pinches in two

Telomeres

Protective caps at the ends of chromosomes that prevent DNA from fraying or sticking together during cell division