Flashcards in Chapter 3 Deck (64)
What differentiates mature cells from immature cells?
Differentiation - mature cells are more specialized.
What is a fertilized ovum?
It is a zygote
Name two large cells
Fertilized zygote and anterior horn cell
What is are the components of a mature cell? Is there an exception?
Nucleus, Cytoplasm, and Cell Membrane.
An exception would be mature red blood cells. Immature red blood cells have a nucleus however it is lost by the time its matured.
What are eukaryotic cells ?
Organisms with a nucleus.
What is a nucleus and what does it contain ?
Large spherical organelle with a double membrane with pores that allow substances into and out of the cell. It contains DNA
A region in the nucleus with no surrounding membrane is called the nucleolus which produces ribosomes (site of protein synthesis).
There is also chromatin - uncoiled DNA and protein - histones. When chromatin condense theyre called chromosomes.
The fluid in the nucleus is the nucleoplasm.
What is the cytoplasm?
The inside of a cell. It is made up of cytosol - fluid portion and organelles.
What is the mitochondria?
Powerhouse of the cell. Produces energy for the cell. Has a double membrane with folds on the inner membrance called cristae. ATP is produced in the inner membrane.
Mature red blood cells have no mitochondria.
Also have DNA and direct the synthesis of some proteins
What are ribosomes?
Responsible for protein production . Made up of RNA. Do not have a membrane, assembled in the nucleolus. Are found free in the cytoplasm or bound to the ER
What is the endoplasmic reticulum?
Network of channels having a single membrane. Connected to the nuclear envelope, cell membrane, and organelles.
rER - has ribosomes attached to it. Synthesize and process proteins, take them to the Golgi apparatus . Found mostly in endocrine glands that secrete hormones.
sER - has no ribosomes, involved with lipid synthesis and detoxification . Found in the liver .
What is the Golgi Apparatus?
System of stacked membraneous sacs cisternae - look like stacked bowls decreasing in size.
Process, package, and transport proteins made in the rER. When done processing the protein is wrapping in a vesicle to be pushed out of the cell by exocytosis.
Difference between Lysosome and Perioxisome?
Lyso- Small, membrane bound . Contain lytic enzymes that can destroy / digest proteins, carbs, etc
Per - Similar but contain peroxidases. Help to break down peroxide , help with detoxification . Found in the liver.
What are Cilia?
Hairline strands outside the cell membrane. Help to propel material throughout the body. Found in mucus membrane
When people smoke they can damaged, therefore particles cannot be moved up the respiratory tract causing the coughing.
What are Flagella?
Like cilia but longer. Found in sperm cell and responsible for mobility.
What are centrioles?
Cylinderical organelles near the nucleus. Have spindle fibres attached to them . Help to pull chromosomes apart during cell division.
What is the cell membrane? What are its characteristics?
Made up of two phosolipid layers - hydrophilic heas pointing outwards and hydrophilic tails pointing in wards.
It is semi permeable
What is passive transport? Different types?
Involves no energy. Molecules move from area of high concentration to area of low concentration
Simple diffusion - lipid soluble substances like O2, CO2 move down the concentration gradient - area between high and low concentration. Movement does not stop, when equilibrium is reached - movement constant
Facilitated Diffusion - Not lipid soluble - K, NA, GL. Need a carrier to move around.
Osmosis - Diffusion of H2O from low to high concentration. If more solid in the cell then inside is hypertonic, outside is hypotonic. If concentration equal then isotonic
Filteration - Molecules move across a membrane due to pressure on the side where the molecules are leaving.
What is active transport?
Requires energy . Molecules move from low to high concentration.
Endocytosis - Formation of vesicle
Phagocytosis - When larger molecules are brought into the cell
Phinocytosis - Liquid brought into the cell.
Exocytosis - Secretion of protein hormones in endocrine glands
Transcytosis - when endo and exo are happening at the same time
NaK pump - Na out of cell and K into . High Na concentration outside the cell, and high K concentration inside the cell . Happens in nerve cells after passage of impluse.
What is interphase?
When the cell is getting ready for mitosis or replicating DNA
What is mitosis?
Cell division and replication. Resulting in two daughter cells with same number and kind of chromosomes as the original nucleus
What is prophase?
First phase. Chromatin condenses to form chromosomes. Each chromosome has two identical sister chromatids joined by a centromere. Centrioles - microtubles move to the opposite ends of the cell forming spindle fibres that attach to the centromeres of the chromosomes.
What is metaphase?
2nd phase. Chromatids line up in the middle or equatorial plate
What is anaphase?
3rd phase . Spindle fibers joining the centromere to the centrioles shorten shorten and move the sister chromatids to the opposite ends of the cell.
What is telophase?
Final phase. Formation of nuclear envelope . Chromosomes unwind to form chromatin. The cell is ready to divide.
What is cytokenesis?
Actual division of the cell. It starts at late anaphase and continues in telophase.
What is Meiosis ?
Cell division required for reproduction - ova and sperm . Instead of 2 identical daughter cells it produces 4 functional sperm cell in men and 1 egg and 3 nonfunctional polar bodies in women .
What is regulation?
The number of times a cell can divide (50-75).
Labile cells - constantly dividing eg - bld cells, skin
Stable cells - dividing when needed - hepatocytes
Permanent cells - cannot multiply - neuron
What are stem cells?
Cells that can become a variety of cells
Embryonic Cells - derived from embryos that develop from eggs fertilized in vitro not taken from eggs fertilized in a womans body
Adult stem cells - present in most organs or tissues in body
What is the major difference between embryonic and adult stem cells?
Embryonic stem cells are totipotent - they can develop into any cell type.
Adult stem cells can only develop into specialized cells of a specific tissue or organ .