Chapter 3 - Cell Biology

Plasma Membrane

Barrier separating intracellular and extracellular environments (keeps thing in and out), holds the cell together, attaches to other cells, and is semipermeable.

Phospholipid Bilayer

two layers of either phospholipids, cholesterol, and glycolipids with hydrophobic outside and hydrophilic inside

Antigen

Cell's ID tag for immune recognition.

Passive transport

no energy required and movement of solute from high to low concentration. Ex: diffusion and osmosis

Diffusion

Movement of solute from an area of higher concentration to an area of lower concentration (moves down the concentration gradient)

Simple diffusion

substances move across the membrane without the help of transport proteins

Facilitated diffusion

integral membrane proteins are used to help the movement

Facilitated diffusion - Channel mediated

substances move down the concentration gradient with assistance (ion channels)

Facilitated diffusion - Carrier mediated

a carrier is attached to the solute to help move it across the membrane and down the concentration gradient

Osmosis

Movement of solute from an area to low concentration to an area of higher concentration (low to high)

Hydrostatic pressure

Pressure applied by fluid on its side of the membrane (more water=more hydrostatic pressure)

Osmotic pressure

pressure that is proportional to the concentration of solutes that cannot cross the membrane

Tonicity

solutions ability to change the volume of its cell by changing its water content

Isotonic solution

osmotic pressure is the same on both sides (cell stays the same)

Hypotonic solution

lower solute concentration outside the cell than inside, water moves into the cell (cell bursts)

Hypertonic solution

lower solute concentration inside the cell than outside, water moves out of the cell (cell shrinks)

Active transport

energy is required to move substances against or up the concentration gradient (low to high)

Primary active transport

Active transport that relies directly on the hydrolysis of ATP to move substances against their concentration gradient (low to high) Ex: Sodium-Potassium pump

Secondary active transport

Energy stored (in a hydrogen or sodium concentration gradient) is used to move other substances against their own concentration gradients and requires symporters/antiporters

Symporters

moves two substances in the same directions (secondary active transport)

Antiporters

moves two substances in opposite directions (secondary active transport)

Endocytosis

phagocytosis ("cellular eating") and pinocytosis (cellular drinking)

Phagocytosis

A type of endocytosis in which a cell engulfs large particles or whole cells

Pinocytosis

takes droplets of fluid outside the cell and brings them inside

Exocytosis

Cells release material through a transport mechanism

Cytoplasm

Gel-like substance (cytosol) within the cell membrane, forms the "cell skeleton," and organizes organelles

Organelles

ribosomes, endoplasmic reticulum, golgi appartus, mitochondria, lysosomes, and centrosomes.

Ribosomes

Organelles responsible for protein synthesis.

Rough Endoplasmic Reticulum

Contains ribosomes that give it a rough texture and continues protein synthesis outside of cell nucleus

Smooth Endoplasmic Reticulum

No ribosomes and is involved in the synthesis of lipids and steroids which make up the cellular membrane

Golgi Apparatus

Packages and ships (secretes) proteins made to go where they're needed in the body (UPS store)

Mitochondria

Known as the 'Powerhouse' of the cell, where ATP is generated.

Lysosomes

digestive organelles that destroy bacteria and clean things up

Centrosome

Provides shape and organization to the cell.

Nucleus

Control center of the cell containing DNA, stores genetic information, and filled with nucleoplasm and nucleoli (DNA/RNA)

Nucleoli

Clusters of proteins, DNA, and RNA that produce ribosomes.

Protein Synthesis

determines the physical and chemical characteristics of the cells (make cell structures, act as hormones, produce antibodies and contract muscles)

Transcription

genetic information in DNA is copied onto a strand of RNA to direct protein synthesis (occurs inside the nucleus)

Translation

The process of reading the mRNA nucleotide sequence to determine the amino acid sequence of a protein (occurs outside the nucleus)

Somatic Cell Division

Any cell in the body other than a germ cell (sperm or oocyte), duplication of all 45 chromosomes (mitosis)

Reproductive Cell Division

The production of germ cells (sperm or oocyte), known as gametes (meiosis)

Mitosis

A type of somatic cell division that copies the 46 chromosomes in one division to make 2 identical cells.

Interphase

The stage where DNA is replicated in the nucleus and organelles duplicate.

Prophase

The beginning of duplication where chromatids are formed.

Metaphase

The stage where chromatids align in the center of the cell.

Anaphase

The stage where each chromatid is separated and moved to opposite poles of the cell.

Telophase

The stage where the outer membrane constricts and pinches the cell in half, creating two identical cells.

Meiosis

The process that copies 23 chromosomes (haploid) from the starting cell (occurs in the gonads)

Apoptosis

Programmed cell death that all cells have, leading to a life span.

Neoplasm

increase in production or lack of cellular death

Where is mRNA produced and what part of the cell does mRNA target, once produced?

Produced in the nucleus (transcription) and targets the rough ER (translation)

Cell

Structural and functional unit of life, can vary in type, size and shape.

Every complete cell has to have:

Plasma membrane, cytoplasm, and nucleus

What is the plasma membrane made of?

phospholipid bilayer and membrane proteins

Semipermeable

Allows certain substances to pass, blocking others.

What makes the plasma membrane semipermeable?

The phospholipid bilayer

Membrane Proteins

Integral (transmembrane) - built into the membrane and found in between fat, Peripheral - used to identify and stick outside the membrane

Which substances have greater permeability?

Lipid soluble substances

How are gradients produced?

By selective permeability

Concentration Gradient

Difference in solute concentration across a membrane.

Integral Proteins

Proteins embedded within a membrane and contains Ion channels (allows specific ion to diffuse across membrane), carriers (gets things across), receptors (can change function of a cell), and enzymes (speed up reactions in the body)

Peripheral Proteins

Proteins attached to the outer membrane surface.

MHC proteins

tells the body what cells belong