Transcript Basic Cell Structure

Basic Cell
Structure
Cells
• Basic building blocks of life
• Understanding of cell
morphology is critical to the
study of biotechnology
Cell
• Smallest living unit of an
organism
• Grow, reproduce, use energy,
adapt, respond to their
environment
Cell
• Many cannot be seen with the
naked eye
• A cell may be an entire organism
or it may be one of billions of
cells that make up the organism
Cells
• Divided and classified in many
ways
• One common classification
method is the presence or
absence of a cell necleus
Nucleus
• Relatively large structure with
a cell
• Directs cell activities
• Some simple single celled
organisms lack a nucleus
Nucleus
• Prokaryotes – have no
nucleus
• Eukaryotes – have a nucleus
Prokaryotes
•
•
•
•
Single celled organism
Kingdom Monera
Lacks a cell nucleus
Internal structure is less
organized than other cells
Prokaryotes
• Genetic info needed is within
the cell
• Two most common – blue
green bacteria and true
bacteria
Blue green
bacteria
• Have ability to produce their
own food like plants
• Most bacteria get their food
from other sources
Prokaryotes
• Less complex than eukaryotes
• Still have many of the basic
internal characteristics
•
•
•
•
•
Common
prokaryote
structures
Cytoplasm
Chromosomal material
Cell membrane and wall
Ribosomes
Some have flagellum for mobility
Eukaryotes
• Organism made up of cells that
have a nucleus
• May be single celled – Kingdom
Protista
• May have billions of cells like
plant and animal kingdoms
Eukaryotes
• Single celled eukaryotes
include paramecia, euglena,
and diatoms
Eukaryotes
• Typically are highly organized
• Infinite number of shapes and
purposes
Eukaryotes
• Human body has at least 85
different cell types
• All eukaryotes have a number
of structures in common
Common
structures
• Organelles – smaller parts of
the cell with specific funtions
• Cell membrane – acts as a
gatekeeper
Cell
membrane
• Controls what enters and leaves
the cell
• Plants, algae and bacteria
typically have a tough outer
structure known as a cell wall
Cell wall
• Provides additional structure and
protects the cell from pressure
caused by movement of water
• Animal cells do not have walls
Cytoplasm
• Organelles are surrounded by a
jelly like substance
• Primary component is water
Nucleus
• Largest and most identifiable part
of the cell
•
•
•
•
Other
organelles
Ribosomes
Mitochondria
Golgi bodies
Endoplasmic reticulum
Other
organelles
• Lysosomes
• Vacuoles
• Chloroplasts in plants
Nucleus
• Brain of the cell
• Site of much of the manipulation
done in biotechnology
Nucleus
• Controls activity of the cell
• Round or oval structure
• Typically found in the middle of
the cell
• Appears darker than surrounding
material
Nucleus
• Surrounded by a membrane that
controls passage of materials in
and out of the area
Nucleus
• Contains DNA
• DNA is located on chromosomes
• Most organisms are diploid –
have two chromosomes for each
trait
Diploid
• Humans – 23 pair
• Goldfish – 90 chrms, 45 pair
Cytoplasmic
Organelles
• Organelles are required for proper cell
function
• Ribosome – make proteins for cellular
use and communication
• May be attached to endoplasmic
reticulum
Endoplasmic
reticulum
• Layered membraneous
• Make and transport proteins
Vacuole
• Large organelle, without specific
shape
• Store waste or raw materials used
in synthesis of proteins
Golgi Bodies
• Golgi apparatus
• Similar to endo. Ret.
• Look like a thick elastic band that
has been folded several times
Golgi Bodies
• Adds modifications to unfinished
proteins
• Makes lysosomes
Lysosome
• Small round
• Store enzymes that break down
food into chemical compounds
• Destroy cell organelles and the
cell itself
Mitochondria
• Energy factories
• Rod shaped
• Change food into molecules that
can be used for energy
Mitochondria
• Contain DNA
• Can replicate themselves
Chlorplast
• Found in plants and some other
organisms
• Contain chlorophyll
•
•
•
•
Cellular
processes
Respiration
Osmosis
Diffusion
Photosynthesis
Respiration
• Cells break down carbohydrates
and other molecules to produce
energy
• Oxidation of glucose is one of
most common forms
Respiration
• Breaking down of sugar into
water, carbon dioxide, and energy
• Energy is used to do the work of
the cell
Osmosis &
Diffusion
• Transport of raw materials,
wastes, and synthesized
materials out of the cell
Diffusion
• Movement of molecules,
especially gases and liquids from
areas of high concentration to
areas of low concentration
Osmosis
• Specific type of diffusion
• Movement of water through a
membrane from areas of high
concentration to areas of low
concentration
Equilibrium
• Diffusion and osmosis happen to
enable a cell to reach equilibrium
Cellular
reproduction
• Three ways
• Fission
• Mitosis
• Meiosis
Fission
• Prokaryotes
• Cell grows larger and makes a second
copy of its DNA
• At some point the cell membrane
divides the cell by the growth of a
transverse septum
Fission
• Two new cells are formed as the
division grows inward from either
side of the cell
• Two cells now called “daughter cells”
• Sometimes known as “binary fission”
Mitosis
• Eukaryotes
• Requires 6 stages
• Interphase, prophase, metaphase,
anaphase, telophase, cytokinesis
Mitosis
• Creates cells that are identical to
the original cell.
• Have the entire compliment of
chromosomes existing in pairs diploid
Meiosis
• Division of sex cells
• Stages of Meiosis I: Interphase I,
prophase I, metaphase I,
anaphase I, telophase I,
cytokinesis I
Meiosis
• Meiosis II
• Interphase II, prophase II,
metaphase II, anaphase II,
telophase II, cytokinesis II
Meiosis
• Each cell receives one
chromosome from each pair
randomly
• Resulting cells have half the
normal number of Chromosomes
- haploid