Cell notes for biology test
What is a eukaryotes, and when did eukaryotes first arise?
A eukaryotes is a cell that is more complex then a prokaryote. Every eukaryotes has a cell membrane, ribosomes, and DNA. The DNA is not floating freely around the cytoplasm like a prokaryote, but it is in the nucleus.
What is a Prokaryote, and when did Prokaryotes arise?
A prokaryote is an organism made from a single prokaryotic cell. The prokaryotes had arisen more than 2.5 billion years ago.
List the responsibilities of the cell membrane.
Controls what enters and leaves the cell.
How are the cells able to recognize various molecules and other types of cells?
The membrane protein called glycoproteins have carbohydrate chains which let them recognize other cells and certain molecules.
Describe the function of the proteins embedded in the cell membrane?
The proteins así in diffusion and in cell recognition.
What structures are common in bother prokaryotes and eukaryotes?
- DNA, RNA, and proteins - ribosomes - cytoplasm - storage granule?
Describe the structures that form the OUTSIDE of a prokaryotic cell.
- They have a cell membrane - they have a cell wall - they are also covered with another structure called the capsule (sticky)
Tail of a phospholipid...
- doen't like water - 2 fatty acid chains - non-polar
Mitochondria
- double membrane, sausage-shaped, inside is folded to increase surface area - provides energy the cell needs to move, divide, produce secretary products?, and contract. Have different shapes depending on cell types
Golgi apparatus
- flat membrane sacs with vesicles ("packages") coming off - membrane-bound structure. Actually a stack of membrane-bound vesicles that package macromolecules for transport around cell
Nucleas
- large, circular structure - surrounded by phospholipids bilayer - nuclear envelope - holds the DNA that shows what the cell does
Head of a phospholipid...
- likes water - polar
Chromosomes
- located in nucleus - is the substance that the DNA condenses into when the cell is splitting
Ribosome
- located in the cytoplasm or on the endoplasmic reticulum - small spheres - are pockets of RNA and protein - site of protein synthesis -has 2 parts: longer and smaller subunits
Cell membrane
- made of lipids and proteins - lipids are called phospholipids (lipid bilayer) - cholesterol adds strength - acts as a protective barrier to the flow of water. Also controls the entry and exit of iodines
Vacuoles
- membrane bound sac - plays roles in intercellular digestion and the release of cellular waste products
Endoplasmic reticulum
- membranes located throughout the cell, usually extending from nucleus Rough: - looks "pebbled" due to the numerous ribosomes on the surface. Protein synthesized on the ribosomes are called in the ER for transport around cell Smooth: - varying functions to show how complex it is. Responsible for production of enzymes. Looks smooth. Different functions depend on specific cell type
Chloroplast
- only found in plants - contains pigment chlorophyll - found in higher plant cells - reason the plant is green - has the ability to absorbe energy from sunlight
Cell wall
- only found in plants - rigid outer structure made of cellulose - protective cell wall made up of polysaccharides. Used as a protective barrier
Central cacuole
- only found in plants - very large water-filled compartment - they tend to be large in plant cells - strong nutrients and waste products, helping cell size during growth and even acting like lysosomes of animal cells
Phospholipids self-assemble into a liquid bilayer. Finish!!!!!!!!!!!!
- phosphate head face towards the water inside and outside of the cell. Tails face the inside of the bilayer - cholesterol imbedded in the ___________
Lysosomes
- sac-like circular organelle - they contain hydrolytic enzymes necessary for intercellular digestion
The plasma membrane...
- separates the cell from its environment - protects the cell - is selectively permeable (controls what enters and leaves the cell) - helps organisms maintain homeostasis (balance or equilibrium) be controlling what enters and leaves the cell
Permeability of a plasma membrane
- small molecules (O2, CO2, and H2O) can easily pass through the membrane - larger molecules, like glucose and proteins, are carries across the membrane
Describe 3 main features inside a prokaryotic cell.
- the prokaryotes don't have a nucleus - they only have a single loop of DNA which floats around freely in the cytoplasm - protein-making bodies called ribosomes also form the cytoplasm
Cytoplasm
- water and organic compounds - it is the stuff inside the cell is suspended in
Define hydrophilic. What part of the bilayer is hydrophilic?
Hydrophilic is when something loves water. The head of a phospholipid loves water.
Define hydrophobic. What part of the bilayer of hydrophobic?
Hydrophobic is when something is afraid or fearing of water. The 2 tails of a phospholipid is afraid of water.
Phospholipids self-assemble into a _____________ (double layer)
Liquid bilayer
What is another name for the cell membrane?
Plasma membrane
When does the movement of materials in and out of the cell NOT require energy?
The cell vibrates constantly which makes small openings in the structure. Those openings then allow water and other mall molecules to pass in and out it the cell without using energy. It is called diffusion.