Anatomy-Cells

the cell

The fundamental structural & functional unit of all organisms

although cells are morphologically different,

cells have many common characteristics

inorganic compounds in all cells

water (75% of cell mass) and electrolytes (acids, bases, salts)

organic compounds in all cells

protein

protein: how are structure and function determined

by number and sequence of amino acids

three examples of protein function

structural, enzymes, hormones

three kinds of carbohydrates

-monosaccharide (simple sugar)

-disaccharide (two sugars linked together)

-polysaccharide (multiple sugars linked together)

lipids are stored as

fats

cholesterol

lipid; precursor to fat, vitamins, and steroid hormones

phospholipids

lipid; major component of cell membrane bilayer

two kinds of nucleic acids

-DNA (chromosomes, genetic info)

-RNA (involved in protein synthesis)

composition of cell membrane

lipids, proteins, carbohydrates

name for general structure of cell membrane

fluid mosaic model

cell membrane functions

1. compartmentalize specific regions for cell-to-cell signaling

2. regulate movements of materials

3. intercellular interactions

selective permeability

only certain substances pass in or out of cell

2 parts of a phospholipid

hydrophilic polar head and hydrophobic non-polar tail

fluid mosaic model traits

-amphipathic phospholipid components arranged in bilayer

-membrane fluid-like

-proteins and carbohydrates float like icebergs in sea of phospholipids

intercellular interactions from cell membrane

communication between cells, place for cell-to-cell adhesions

what types of molecules can the cell membrane recognize

hormones, antibodies, enzymes, and other signaling molecules

organelles

Small functional structures within the cell

nucleus

dense mass containing chromatin, the nuclear envelope, and the nucleolus

chromatin

DNA and protein

chromosome

condensed form in nucleus

chromatid

half of duplicated chromosome

nuclear envelope

membrane surrounding nucleus

nucleolus

site of RNA synthesis

nucleus functions

1. stores genetic information

2. involved in cellular division

3. regulates cellular metabolism and activity of all organelles

cytoplasm definition

substance within the cell

4 components of the cytoplasm

cytosol, organelles, cytoskeleton, and inclusions

cytosol

fluid within cell, varies in composition depending on cell type

cytoskeleton

proteins that maintain cell shape and structure; involved in movement and compartmentalize organelles

inclusions

small substance associated with cell function, not organelles

ribosome structure and function

composed of protein and RNA, site of protein synthesis

cells producing a large amount of proteins have ______

more ribosomes present

endoplasmic reticulum: structure and function

-membranous network of channels located throughout the cytoplasm; continuous with nuclear envelope

-provides a channel for communication and transport of substances throughout the cell

two types of ER

rough and smooth

rough ER

has multiple ribosomes on surface; responsible for manufacture and transport of protein

smooth ER

responsible for lipid production, metabolism, and calcium storage

golgi apparatus

-stacks of flattened sacs

-storage of protein, packages materials into vesicles or granules for storage or secretion

mitochondria- structure and function

-rod shaped, has internal folds called cristae

-cellular respiration, production of energy from ATP for other cellular functions

microtubules

Small, hollow tubules which run throughout the cytoplasm; Formed by protein tubulin

mircotubules function

provide a cellular framework, serve as conducting channels through which substances pass through the cytoplasm; structural components of centrioles and cilia

centrosome

located near nucleus, 1 or 2 per cell, houses 2 centrioles

centrioles

cylindrically shaped organelles, composed of 9 triplets of microtubules; 2 per cell, located near nucleus

centrosome and centrioles play an important role in

cell divison

microfilament: structure and function

-Thin strands of protein which are usually found in bundles

-provide skeletal support and are associated with contractile activities and cell locomotion (actin/myosin)

microfilaments are abundant in

muscle cells

microvilli structure and function

-Finger-like projections of cell membrane made by in-folding

-Increase surface area of cell membrane, Facilitates transport

Cilia- structure and function

-Cytoplasmic projections made of microtubules

-Move in a wave-like fashion to move mucous

cellular adhesions

Junctional complexes; specialized regions of cell-to-cell contact

types of cellular adhesions

tight junctions, desmosomes, gap junctions

tight junctions

Form tight seal between cells

desmosomes

“Spot-weld” cells together

gap junctions

Allow for cell-to-cell exchange and communication