Chapter 4: Inside the Cell

Cells

smallest unit of life

Why are cells limited in size?

Cells are small to have a larger ratio surface area to internal volume that would allow them to move nutrients into the cell and remove wastes outside the cell. It is important for cell function

Plasma membrane

serves as boundary between the outside and the inside of a cell.

It is a selective barrier passage of gases, nutrients, and waste

Phospholipid bilayer

Prokaryotic

Found in Domain Archaea and Bacteria

No nucleus, but has Nucleoid (DNA in a single circled chromosome), No membrane-bound organelles, Cytoplasm bound by the plasma membrane.

Eukaryotic

Found in Domain Eukarya

DNA is in the nucleus (a membranous nuclear envelope), has membrane-bound organelles, cytoplasm is between plasma membrane and nucleus, has a larger size the prokaryotic

Prokaryotic and Eukaryotic

has lipid bilayer, has cytosol (inner fluid), chromosomes (genes), and Ribosomes (make proteins)

membrane proteins

Embedded proteins that perform specific functions for the cell membrane.

Junction = assist in cell-to-cell adhesion and communication

channel protein

allows passage of only one or a few specific molecules to move readily through the membrane (ex: aquaporins in kidneys)

transport proteins

allow passage of hydrophilic substances across the membrane

cell recognition proteins

recognizes our own cells from foreign cells (ex: glycoproteins)

receptor proteins

needs signal molecules to change shape and bring cellular response

enzymatic proteins

participate in metabolic reactions

junction proteins

assist in cell-to-cell adhesion and communication

Nucleus

Stores genetic information (DNA)

Site of DNA transcription

Nucleolus

where rRNA (ribosomal RNA) is made

nuclear envelope

A double membrane with pores that surrounds the nucleus in the cell

Ribosomes

Makes proteins

Endoplasmic Reticulum

assists in the production, processing, and transport of proteins and in the production of lipids.

(Biosynthesis Factory)

Smooth ER

Makes lipids, detoxifies poisons and enzyme production

Rough ER

studded with ribosomes and synthesizes membrane-bound proteins (membrane factory) and makes transport vesicles

Golgi apparatus

Flattened membranous sacs

it receives, modifies and ships materials into transport vesicles (warehouse)

Vesicles

small membrane sacs that specialize in moving products into, out of, and within a cell

Lysosomes

digestive compartments

digests macromolecules or old cell parts

Vacuole

Cell organelle that stores materials such as water, salts, proteins, and carbohydrates

contractile vacuole

pump water out of cell (in protists)

central vacuole

in a mature plant cell, stores water and organic molecules

Food vacuoles are formed by

phagocytosis (cell-eating)

Chloroplasts

Site of photosynthesis

has its own DNA and ribosomes

has chlorophyll

Solar energy is used to synthesize carbs

Mitochondria

breakdown carbs to produce ATP

site of cellular respiration

present in BOTH animals and plants

has its own DNA and ribosomes

Cytoskeleton

A network of fibers that holds the cell together, helps the cell to keep its shape, and aids in movement

cilia and flagella function

movement of cell

Cilia is shorter than flagella

Cell Wall (NOT found in ANIMALS)

maintains shape and provides support to the cell

Plasmodesmata

channels between adjacent plant cells that allows exchange of water and small molecules between cells