CELL STRUCTURES

WFHS BIOLOGY FALL 2014

FUNCTION OF A PLASMA MEMBRANE

• THE PLASMA MEMBRANE CONTROLS HOW, WHEN,

AND HOW MUCH SUBSTANCES ENTER AND LEAVE

THE CELLS

• SELECTIVE PERMEABILITY OF THE PLASMA

MEMBRANE ALLOWS SOME SUBSTANCES TO PASS

THROUGH WHILE KEEPING OTHERS.

• A CELL’S SURVIVAL DEPENDS ON MAINTAINING

BALANCE, THIS IS CALLED HOMEOSTASIS.

• THE PLASMA MEMBRANE IS THE CELL STRUCTURE

PRIMARILY RESPONSIBLE FOR HOMEOSTASIS

STRUCTURE OF THE PLASMA MEMBRANE

• LIPIDS ARE MADE OF GLYCEROL AND 3 FATTY

ACIDS.

• A PHOSPHOLIPID A PHOSPHATE GROUP AND

ONLY 2 FATTY ACIDS.

• POLAR HEAD AND 2 NONPOLAR TAILS

• THE PLASMA MEMBRANE IS MADE UP OF TWO

LAYERS ARRANGED TAIL-TO-TAIL

• THIS IS CALLED A PHOSPHOLIPID BILAYER.

STRUCTURE CONT.

• POLAR HEAD CLOSEST TO WATER BECAUSE

WATER IS ALSO POLAR

• POLAR SUBSTANCES WILL NOT PASS

THROUGH THE NONPOLAR MIDDLE.

• TRANSPORT PROTEINS MOVE NEEDED

SUBSTANCES THROUGH THE MEMBRANE:

SELECTIVE PERMEABILITY

• EXAMPLES:

• CELL MEMBRANE

• NUCLEAR MEMBRANE

• MEMBRANE OF ORGANELLES

FLUID MOSAIC MODEL

• AS THE INDIVIDUAL MOLECULES MOVE AROUND, A PATTERN, OR MOSAIC, IS FORMED ON THE SURFACE OF THE PLASMA MEMBRANE

a. unsaturated fats.

b. carbohydrates.

c. lipids.

d. proteins.

•Polysaccharides are

Polysaccharides are

CELL MEMBRANE

• DESCRIPTION:

• OUTSIDE COVERING OF CELL MADE OF LIPID

BILAYER

• FUNCTION:

• BARRIER BETWEEN CELL AND ITS ENVIRONMENT

• CONTROLS WHAT SUBSTANCES CAN ENTER OR

LEAVE THE CELL

• PROVIDES SUPPORT AND PROTECTION,

ESPECIALLY IN CELLS WITHOUT A CELL WALL

• ANALOGY

NUCLEAR MEMBRANE

• DESCRIPTION:

• DOUBLE-LAYER MEMBRANE SURROUNDING

THE NUCLEUS

• FUNCTION:

• SEPARATES NUCLEOPLASM FROM

CYTOPLASM

• ANALOGY

CELL WALL

• DESCRIPTION:

• RIGID OUTER LAYER

• OUTSIDE OF CELL MEMBRANE

• FUNCTION:

• SUPPORT

• PROTECTION

• HELPS CELL MAINTAIN ITS SHAPE

• ANALOGY

Carbohydrates Proteins

Nucleic acids Lipids

Which of the following macromolecules is a

prominent part of animal tissue that

functions in insulation, helping animals

conserve heat?

CYTOPLASM

• DESCRIPTION:

• JELLY-LIKE SUBSTANCE THAT FILLS THE CELL AND

SURROUNDS THE ORGANELLES

• FUNCTION:

• FILLS SPACE BETWEEN ORGANELLES

• CONTAINS MATERIALS NEEDED BY THE

ORGANELLES

• ANALOGY

WHAT IS THE CELL THEORY?

RIBOSOMES

• DESCRIPTION:

• MADE OF PROTEIN AND RNA

• VERY SMALL, SPHERICAL SHAPED

• FUNCTION:

• MAKE PROTEINS

• ANALOGY

FLAGELLA

• DESCRIPTION:

• LONG, THREAD-LIKE EXTENSION OF A

CELL

• FUNCTION:

• HELPS CELL MOVE

• ANALOGY

CILIA

• DESCRIPTION:

• SHORT, HAIR-LIKE PROJECTION ON

THE CELL SURFACE

• FUNCTION:

• USED TO SWEEP AWAY THINGS

FROM THE CELL SURFACE OR HELP

THE CELL MOVE THROUGH FLUID

• ANALOGY

NUCLEUS

• DESCRIPTION:

• CORE, CENTRAL PORTION OF CELL

• FUNCTION:

• CONTAINS GENETIC INFORMATION (DNA)

• DIRECTS CELL ACTIVITIES

• ANALOGY

NUCLEOLUS

• DESCRIPTION:

• ROUND STRUCTURE WITHIN NUCLEUS

• MADE OF PROTEIN AND RNA

• FUNCTION:

• MAKES RIBOSOMES

• ANALOGY

CHLOROPLAST

• DESCRIPTION:

• OVAL OR BEAN SHAPED STRUCTURE WITH

GREEN COLOR

• FUNCTION:

• HELPS CAPTURE SUNLIGHT TO PRODUCE

FOOD (ENERGY) FOR PLANTS

• ANALOGY

GOLGI APPARATUS

• DESCRIPTION:

• FLATTENED SACS CALLED CISTERNAE

• FUNCTION:

• MODIFIES AND PACKAGES MATERIALS

CREATED IN THE CELL FOR

TRANSPORT (INSIDE OR OUTSIDE OF

THE CELL)

• ANALOGY

LYSOSOME

• DESCRIPTION:

• SMALL SACS

• FUNCTION:

• USE DIGESTIVE ENZYMES TO BREAKDOWN

OLD/WORN-OUT ORGANELLES, VIRUSES OR

BACTERIA, AND/OR FOOD PARTICLES

• ANALOGY

MITOCHONDRION

• DESCRIPTION:

• SPHERICAL OR ROD-SHAPED

• INNER AND OUTER MEMBRANES

• FUNCTION:

• CONVERTS SUGARS INTO ATP (ENERGY) FOR

THE CELL

• ANALOGY

PLASTID• DESCRIPTION:

• DOUBLE-MEMBRANE BOUND

ORGANELLE

• FUNCTION:

• INVOLVED IN FOOD STORAGE;

FUNCTION DEPENDS MOSTLY UPON

WHICH PIGMENTS ARE PRESENT

• ANALOGY

ROUGH ENDOPLASMIC RETICULUM

• DESCRIPTION:

• SYSTEM OF MEMBRANOUS TUBES AND SACS

WITH RIBOSOMES ON THE SURFACE (MAKING IT

APPEAR ROUGH)

• FUNCTION:

• HELPS MAKE AND TRANSPORT NEW PROTEINS

TO GOLGI APPARATUS OR OUTSIDE OF THE CELL

• ANALOGY

SMOOTH ENDOPLASMIC RETICULUM

• DESCRIPTION:

• SYSTEM OF MEMBRANOUS TUBES AND SACS

• FUNCTION:

• MAKES LIPIDS

• CREATES AND STORES STEROIDS

• STORES IONS THAT CELLS MIGHT NEED

• METABOLIZES CARBOHYDRATES

• ANALOGY

VACUOLE

• DESCRIPTION:

• SACS: SMALLER IN ANIMAL CELLS, LARGER IN

PLANT CELLS

• FUNCTION:

• STORE A VARIETY OF THINGS SUCH AS

WATER, NUTRIENTS, OR WASTE PRODUCTS

• ANALOGY

VESICLE

• DESCRIPTION:

• SMALL SACS

• FUNCTION:

• STORES, TRANSPORTS, OR DIGESTS

MATERIALS WITHIN THE CELL

• ANALOGY

EXAMPLES FROM STARR

HISTORY OF CELLS

• A CELL IS THE BASIC STRUCTURAL AND FUNCTIONAL UNIT OF ALL

LIVING THINGS.

• 1665, ROBERT HOOKE MADE THE FIRST SIMPLE MICROSCOPE

• HOOKE USED THE MICROSCOPE TO LOOK AT A PIECE OF CORK,

WHICH IS THE DEAD CELLS OF OAK BARK. HE SAW SMALL BOX-LIKE

SHAPED STRUCTURES IN THE CORK, WHICH HE CALLED CELLULAE.

NOW WE KNOW THEM AS CELLS.

• 1838, MATTHIAS SCHLEIDEN DETERMINED THAT ALL PLANTS ARE

COMPOSED OF CELLS.

• THEODOR SCHWANN DETERMINED ALL ANIMAL TISSUES WERE MADE

OF CELLS

PRINCIPLES OF CELL THEORY

• 1. ALL LIVING ORGANISMS ARE MADE UP OF ONE OR MORE CELLS. AN ORGANISM CAN HAVE ONE OR MANY CELLS. MOST PLANTS AND ANIMALS HAVE MANY CELLS.

• 2. THE CELL IS THE BASIC UNIT OF ORGANIZATION IN LIVING ORGANISMS. EVEN IN COMPLEX ORGANISMS SUCH AS HUMANS, THE CELL IS THE BASIC UNIT OF LIFE.

• 3. ALL CELLS COME FROM LIVING CELLS. CELLS PASS COPIES OF THEIR GENETIC MATERIAL ON TO THEIR DAUGHTER CELLS. CELLS CONTAIN HEREDITARY INFORMATION THAT PASSES FROM CELL TO CELL DURING CELL DIVISION.