Transcript Cells, Tissues, and Organs

Cells, Tissues, and Organs
Chapter 4
Modern Cell Biology Makes 6
Assumptions:
1. All living material is made up of cells or
products of cells
2. All cells are formed from previously
existing cells
-cell division
-fusion of sperm and egg
3. Most elementary unit of life
4.Every cell is bound by a plasma
membrane
5. All cells have strong biochemical
similarities
6. Most cells are small
-.001cm (.00004 inches) in length
3 functions of most cells:
1. Maintenance
2. Synthesis of cell products
3. Cell division
Cell Membrane:
• Encloses the cell
Cytoplasm:
• Material in the cell membrane that
contains organelles and granules in
suspension
Examples of organelles:
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Golgi apparatus
Nucleaus
Ribosomes
Centrioles
Microfilaments
Microtubles
Lysosomes
Storage particles
Plasma Membrane:
• Cells are surrounded by this thin
membrane of lipid (fat) and protein
• Controls the transport of molecules in and
out of the cell
• Serves as the boundary between the cell
and surrounding tissue
Nucleus:
• Enclosed by a nuclear envelope, or
membrane, with pores
Nucleoli:
• Discrete structures in the nucleus
• Site of RNA synthesis
Chromosomes in the nucleus:
• Contain DNA
• Carries hereditary information
The nucleus directs the activity of
the cell:
• Example: information is transcribed into
the RNA, which serves as a messenger.
Messenger moves out of the nucleus to
the ribosome where it guides the synthesis
of protein.
Ribosomes:
• Made of RNA and protein
• Site of protein synthesis
Endoplasmic Reticulum:
• A complex set of membranous structures
• Rough or smooth
• Rough = large amounts of protein
Golgi Body:
• Membrane mixture found near nucleus
• Accumulates secreted lipids and proteins
Mitochondria:
• Almost all of the energy passes through
this molecule before being used in cell
function
Microfilaments:
• Long, thin rods that
contract
• Responsible for
movement of cells
Lysosomes:
• Large number of enzymes are stored
Morphogensesis:
• Process of cell development
• Each cell contains the same total genetic
information that was present in the
fertilized egg
• Cells aren’t identical because genes are
controlled (switched on and off) by various
biochemical processes
Cell Division Depends On:
• 1. copying of DNA
• 2. orderly separation of the products of this
copy
Chromatids:
• Each chromosome contains two sister
chromosomes called this
6 Stages of Mitosis:
1.
2.
3.
4.
5.
6.
Prophase
Prometaphase
Metaphase
Anaphase
Telophase
Interphase
Prophase
Metaphase
Anaphase
Telephase
Interphase
Meiosis:
• Produce gametes (sex cells)
• 2 cell divisions
• Reduce number of chromosomes
Meiosis Stages:
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Prophase with 5 sub-stages
Prometaphase
Metaphase
Anaphase
Interphase
• Only one in four of the female gametes is
functional because the division of
cytoplasm is unequal
• The functional ovum requires more
cytoplasm to serve as food for the
developing ovum
• Fertilization: restores the cell to the
original number of chromosomes which
was reduced during meiosis
• Humans: 46 chromosomes
• Horse: 64 chromosomes
DNA consists of 3 components:
• Deoxyribose sugar
• Phosphate
• 4 nitrogen bases:
A – Adenine
T – Thymine
G - Guanine
C - Cytosine
Tissue:
• Structured groups of cells specialized to
perform a common function necessary for
the survival of the horse
Classification of Tissues:
• Nerve
• Epithelial (cover external and cushion
internal)
• Muscle (cardiac)
• Connective (tendons and ligaments)
• Fluid (blood and lymph)