Chapter 5 Flashcards
When was the word cell first used to refer to the microscopic units of life
1665 by British scientist Robert Hooke while he was looking at cork under a microscope
Who was the first person to observe cells?
Anton Van Leeuwenhoek
What is cell theory and who made it?
Theodor Schwann and Matthias Jakob Schleiden, to propose that cells are the basic building blocks of all living things. Around 1850, a German doctor named Rudolf Virchow was studying cells under a microscope when he happened to see them dividing and forming new cells. He realized that living cells produce new cells through division. Based on this realization, Virchow proposed that living cells arise only from other living cells.
The ideas of all three scientists — Schwann, Schleiden, and Virchow — led to cell theory, which is one of the fundamental theories unifying all of biology. Cell theory states that:
All organisms are made of one or more cells.
All the life functions of organisms occur within cells.
All cells come from already existing cells.
What is cell theory and who made it? (simple version)
Idea: All organisms are made of one or more cells, all cells come from existing cells, and all th life functions of organisms occur within the cell.
People: Theodor Schwann, Matthias Jakob Schleiden, and Rudolf Virchow.
Milestone in Microscope development:
Leeuwenhoek made his own microscope lenses that were very powerful.
1800’s light microscopes reach their limit.
1950’s electron microscope is created and spawns the field of molecular biology
What are the 4 structure shared by all cells?
Plasma membrane, cytoplasm, Ribosomes, and DNA
What is the plasma membrane?
a thin coat of lipids that surrounds a cell. It forms the physical boundary between the cell and its environment, so you can think of it as the “skin” of the cell.
Cytoplasm
Cytoplasm refers to all of the cellular material inside the plasma membrane. Cytoplasm is made up of a watery substance called cytosol and contains other cell structures such as ribosomes.
Ribosomes
Ribosomesare structures in the cytoplasm where proteins are made.
DNA
DNAis a nucleic acid found in cells. It contains the genetic instructions that cells need to make proteins.
Plasma Membrane
Theplasma membrane(also called the cell membrane) is a thin coat of lipids that surrounds a cell. It forms the physical boundary between the cell and its environment, so you can think of it as the “skin” of the cell.
Why are cells tiny?
To carry out life processes, a cell must be able to quickly pass substances into and out of the cell.
Anything that enters or leaves a cell must cross its outer surface. Itis this need to pass substances across the surface that limits how large a cell can be.
What is the nucleus of a cell?
A structure in the cytoplasm that is surrounded by a membrane (the nuclear membrane) and contains DNA.
Based on whether or not they have a nucleus, there are two basic types of cells: prokaryotic cells and eukaryotic cells.
What is a prokaryotic cell?
Cells without a nucleus
What type of organisms are prokaryotic cells found in?
SIngle-celled organisms.
The DNA is in the cytoplasm instead of a nucleus.
What are Eukaryotic cells?
Cells that contain a nucleus.
What are organisms with eukaryotic cells called?
Eukaryotes
What do eukaryotic cells contain beside a nucleus?
Organelles.
What is an organelle?
A structure within the cytoplasm that performs a specific function for the cell.
What is a mitochondria?
An organelle that provides energy to the cell?
What is a vacuole?
An organelle that stores substances in the cell.
Who can carry out more functions? Eukaryotes or Prokaryotes?
Eukaryotes because they have organelles to do jobs for them.
What is the correlation ebtween cell shape and cell function?
Cell shape impacts cell function and perhaps vice versa?
What is the Plasma Membrane?
A structure that forms a barrier between the cytoplasm inside the cell and the environment outside the cell.
What are the functions of the plasma membrane?
-Protect and support the cell
-Control everything that enters and leaves cell
-Some may have extensions like flagella or cilia that can help the cell to move OR sweep foreign particles
What is the cell membrane made of?
Mainly Phospholipid Bilayer
Phospholipids are made of fatty acids and alcohol
Consists of 2 layers of phospholipids: 1 layer is water loving (hydrophilic), and 1 layer is water hating (hydrophobic)
What is the cell membrane made of besides phospholipids
Mainly proteins and lipids. Some sugars too.
What is another good reason to not smoke?
Smoking can have devastating effects on the body’s ability to protect itself from repeated, serious respiratory infections, such as bronchitis and pneumonia.
What are Cilia?
Micro-hairs that ling the respiratory, reproductive, and digestive systems. They trap and remove dust, germs, and other foreign particles.
What is cytoplasm?
(Think of a plastic bag filled with jello)
A thick (usually) colorless SOLUTION that fills each cell and is enclosed by the cell membrane.
The cytoplasm houses all of the organelles
What is nucleoplasm?
Watery substance found in the nuclei of eukaryotic cells
What is cytosol?
The liquid part of the cytoplasm that surrounds the organelles
It is composed of about 80 percent water and also contains dissolved salts, fatty acids, sugars, amino acids, and proteins such as enzymes. These dissolved substances are needed to keep the cell alive and carry out metabolic processes. For example, enzymes dissolved in cytosol break down larger molecules into smaller products that can then be used by organelles of the cell. Waste products are also dissolved in the cytosol before they are taken in by vacuoles or expelled from the cell.
KNow this about Prokaryotic cells
Though prokaryotic cells do not have organelles (they do haveribosomes), they still have cytoplasm. It is within the cytoplasm that most cellular activities occur, including the many metabolic pathways that occur within organelles, such asphotosynthesisand aerobicrespiration.
What is a cytoskeleton?
A framework of protein scaffolds that structures the cytoplasm and the cell
What are 3 main kinds of cytoskeleton fibers? (simple version?
microtubules,intermediatefilaments, and microfilaments.
What are microtubules?
Microtubules, are the thickest of the cytoskeleton structures. They are most commonly made of filaments which are polymers of alpha and beta tubulin, and radiate outwards from an area near the nucleus called the centrosome.Tubulin is the protein that forms microtubules. Two forms of tubulin, alpha and beta, form dimers (pairs) which come together to form the hollow cylinders. The cylinders are twisted around each other to form the microtubules. Microtubules help the cell keep its shape. They hold organelles in place and allow them to move around the cell, and they form the mitotic spindle duringcell division. Microtubules also make up parts of cilia and flagella, the organelles that help a cell move.
What are microfilaments?
Microfilaments, are made of two thinactinchains that are twisted around one another. Microfilaments are mostly concentrated just beneath thecell membrane, where they support the cell and help the cell keep its shape. Microfilaments form cytoplasmatic extentions, such as pseudopodia andmicrovilli, which allow certaincellsto move. The actin of the microfilaments interacts with the protein myosin to cause contraction in muscle cells. Microfilaments are found in almost every cell, and are numerous in muscle cells and in cells that move by changing shape, such as phagocytes (whitebloodcells that search the body for bacteria and other invaders).
What are intermediate filaments?
Intermediate filamentsdiffer in make-up from one cell type to another.Intermediatefilaments organize the inside structure of the cell by holding organelles and providing strength. They are also structural components of the nuclear envelope. Intermediate filaments made of the protein keratin are found in skin, hair, and nails cells.
Cells will go _____ if they do not get enough nutrients.
Dormant
What are microtubules? (Simple version)
Microtubules are the thickest of the cytoskeleton structures and are most commonly made of filaments which are polymers of alpha and beta tubulin.
What are microfilamens (Simple Version)
Microfilament are the thinnest of the cytoskeleton structures and are made of two thin actin chains that are twisted around one another.