TRANSPORT OF MATERIAL ACROSS MEMBRANE
ACTIVE TRANSPORT
The movement of molecules or ions
against a concentration gradient.
Three Main Types
1. Endocytosis
- is the process of actively
transporting molecules into the cell
by engulfing it with its membrane
Phagocytosis- a way of
"cell eating" that helps
organisms feed,defend,
and clean themselves.
Pinocytosis- a way of "cell
drinking" that lets cells
absorb fluids and nutrients
from outside.
Receptor Mediated
Endocytosis- a process in
which cells absorb
molecules by the inward
budding of the plasma
membrane.
2. Exocytosis
- is a process that moves materials
from inside a cell to the outside by
using energy and vesicles. Also
helps cells to get rid of waste
products and toxins, and to
maintain their shape and size.
3. Protein Pumps
- transport ions across a membrane
when the concentration gradient is
low.
Cytoplasm of a Cell
-jellylike substance enclosed by
cell membrane.
-provides a medium for chemical
reactions to take place.
-contains organelles to carry out
specific jobs.
The Control organelle
Nucleus
-controls the normal activities of
the cell.
-contains the DNA in
chromosomes.
-bounced by a nuclear envelope
(membrane) with pores.
-usually the largest organelle.
-Each cell has fixed number of
chromosomes that carry genes
Nuclear Envelope
Chromosomes
-Double membrane surrounding
nucleus - DNA is condensed and wrapped
around proteins forming a
-also called a nuclear membrane. chromosomes in dividing cells.
-contain nuclear pores for materials What does DNA do?
to enter and leave the nucleus.
-DNA is the hereditary material of
Chromatin the cell
- DNA is spread out and appears as -Genes that make up the dna
a chromatin in non-dividing cells. molecule code for different proteins
Nucleolus Two Types
-Inside nucleus 1. Rough Endoplasmic Reticulum
-disappears when cell divides -Has ribosomes on its surface
-makes ribosomes that make -makes membrane proteins and
proteins protein for export out of cell
-responsible for manufacturing -proteins are made on rough ER
ribosomal units or ribosomes.
-threaded into the interior of the
Ribosomes rough ER to be modified and
transported
-protein synthesis
2. Smooth Endoplasmic Reticulum
-Makes membrane lipids (steroids)
-regulates calcium (muscle cells)
-destroy toxic substances (liver)
-absence of ribosomes
-lipid synthesis
-Made of PROTEINS and rRNA Endomembrane System
-Protein factories for cell
-join amino acids to make proteins
through protein synthesis
-can be attached to Rough ERor be
free
Endoplasmic Reticulum
-Network of half hollow membrane
tubules -connects to nuclear
-Includes nuclear membrane
envelope and cell membrane
connected to ER connected to cell
-function in synthesis of cell membrane (transport).
products and transport
Golgi Bodies rough ER and then transferred to
the Golgi apparatus for further
processing.
- At least some lysosomes probably
arise by budding from the trans face
of the Golgi apparatus.
- The three-dimensional shapes of
these proteins protect vulnerable
bonds from enzymatic attack.
-Look like a stack of pancakes -Contain digestive enzymes, break
down food, bacteria, and worn out
-modify, sort, and package cell parts for cells
molecules from ER for -storage or
transport out of cell -Programmed for cell death
(APOPTOSIS)
-consist of flattened membranous
sacs- cisternae. -Lyse & release enzymes to break
down & recycle cell parts
-Have a shipping side (trans face) -
"on the opposite side" and receiving - Cells take in food by phagocytosis
side (cis face) - "on the same side" -Lysosomes digest the food & get
-receive proteins made by ER rid of wastes.
-transport vesicles with modified Vacuoles
proteins pinch off the ends. -Food vacuoles, formed by
Lysosomes phagocytosis
-Many unicellular eukaryotes
living in fresh water have
contractile vacuoles that pump
excess water out of the cell.
-Mature plant cells generally
contain a large central vacuole.
-The solution inside the central
vacuole, called cell sap, is the plant
cell's main repository of inorganic
- Hydrolytic enzymes and ions, including potassium and
lysosomal membrane are made by chloride.
-The central vacuole plays a major
role in the growth of plant cells
-In plants, they store Cell Sap
-Includes storage of sugars,
proteins, minerals, lipids, wastes,
salts, water, and enzymes
Mitochondrion
-"Powerhouse" of the cell
-Generate cellular energy (ATP)
-More active cells like muscle cells
have MORE mitochondria
- Both plants & animal cells have
mitochondria
- Site of CELLULAR
RESPIRATION (burning glucose)
