Chapter 7: Cell Structure and Function Flashcards
What is a Prokaryotes cell?
Smaller and simpler than Eukaryotic cells
Does not have a nucleus
Examples of an organism that is a prokaryotes cell is bacteria and archaea.
What is a Eukaryotic cell?
Bigger and more complex than prokaryotic cells
Contain a nucleus
Examples of organisms that are Eukaryotic cells are plants, animals, fungi, and protists.
What is a nucleus?
A nucleus is a large membrane-enclosed structure that contains the cell’s genetic material in the form of DNA.
Controls many of the cell’s activities, makes proteins and other important molecules.
What are organelles?
They are specialized organs known as “little organs.”
Cell biologists divide the eukaryotic cell into what two major parts?
The nucleus and cytoplasm.
What is a cytoplasm?
A cytoplasm is the portion of the cell outside the nucleus.
What is a nuclear envelope?
A nuclear envelope is composed of two membranes.
Dotted with thousands of nuclear pores, and allows material to move into and out of the nucleus.
What is chromatin?
Chromatin is a granular material you see in the nucleus. It consists of DNA bound to protein.
Spread throughout the nucleus.
When the cell divides, chromatin condenses to form chromosomes.
What is a chromosome?
A chromosome is a distinct, threadlike structure that contains the genetic information that is passed from one generation of cells to the next.
What is a nucleolus?
A small, dense region inside the nuclei/nucleus. It is where the assembly of ribosomes begins.
What is a ribosome?
Where proteins are assembled.
Ribosomes are small particles of RNA and protein found throughout the cytoplasm.
What is endoplasmic reticulum? Rough?
The site where lipid components of the cell membrane are assembled, along with proteins and other materials that are exported from the cell.
Rough- Ribosomes are found on the rough endoplasmic reticulum.
Newly made proteins leave these ribosomes and are inserted into the Rough ER, where they may be chemically modified.
Rough ER also produces large amounts of protein for export.
What is endoplasmic reticulum? Smooth?
Ribosomes are not found on this surface.
Smooth ER contains collections of enzymes that perform specialized tasks, like the synthesis of membrane lipids and the detoxification of drugs.
A cell that plays a big role of detoxifying drugs is the liver cell, and it often contains large amounts of smooth ER.
What is the Golgi apparatus?
The Golgi apparatus’s function is to modify, sort, and package proteins and other materials from the endoplasmic reticulum for storage in the cell or secretion outside the cell.
What is a lysosome?
A lysosome is a small organelle that Is filled with enzyme. A function is the digestion or breakdown of lipids, carbohydrates, and proteins into small molecules that can be used by the rest of the cell.
What is a vacuole?
A vacuole is a saclike structure that stores materials like water, salts, proteins, and carbohydrates.
What is homeostasis?
Homeostasis is the maintenance of a controlled internal environment. An example is when the control of water content within the cell.
What is a mitochondria?
A mitochondria is an organelle that converts chemical energy stored in food into compounds that are more convenient for the cell to use.
Mitochondria is enclosed by two membranes, the outer membrane and the inner membrane. The inner membrane is folded up inside the organelle.
What is a chloroplast?
A chloroplast is an organelle that captures the energy from sunlight and converts it into chemical energy through a process called photosynthesis. Chloroplast is the biological equivalent of solar power plants. Like the mitochondria, chloroplast is also surrounded by two membranes. Inside the organelle are large stacks of other membranes, which contain the green pigment chlorophyll.
What is a cytoskeleton?
A cytoskeleton is a supporting structure. It helps the cell maintain its shape. The cytoskeleton is also involved in movement. Two principal protein filaments that make up the cytoskeleton are microfilaments and microtubules.
What is a microfilament?
A microfilament is a threadlike structure made of a protein called actin. They form extensive networks in some cells and supports the cell, also helps the cell move. Microfilament assembly and disassembly are responsible for the cytoplasmic movements that allow cells to crawl along surfaces.
What is a microtubule?
A microtubule is a hollow structure made up of proteins known as tubules. They maintain the cell shape and are important for cell division, where they form a structure called the mitotic spindle, which helps separate chromosomes.
What is a centriole?
Located near the nucleus. They help organize cell division. Not found in plant cells.
What is a cell membrane?
A cell membrane is a thin, flexible barrier where the cells are surrounded. It is also known as the plasma membrane because many cells in the body are in direct contact with the fluid portion of the blood- the plasma.
Also regulates what enters and exits the cell, protection and support.
What is a cell wall?
It is a strong supporting layer around the membrane.
Provides protection and support to the cell.
Difference between animal cells and plant cells?
Animal cells have centrioles, centrosomes (discussed under the cytoskeleton), and lysosomes, whereas plant cells do not. Plant cells have a cell wall, chloroplasts, plasmodesmata, and plastids used for storage, and a large central vacuole, whereas animal cells do not.
Similarities between animal cells and plant cells?
Nucleus, cell membrane, cytoplasm and mitochondria are four cell components that are found in both animal and plant cells.
What is a lipid bilayer?
A lipid bilayer is a double-layered sheet. This lipid bilayer gives cell membranes a flexible structure that forms a strong barrier between the cell and is surroundings.
Function of a carbohydrate chain?
They act like chemical identification cards. Usually they are attached to protein molecules.
What is a phosphate head?
A single phospholipid molecule has a phosphate group on one end, called the “head.” Inside phospholipid bilayer. Hydrophilic (water-loving)
What is a fatty acid tail?
Two side-by-side chains of fatty acids that make up the lipid “tails. ” Hydrophobic (water-fearing)
What is diffusion?
Diffusion in a solution, particles move constantly. The particles move from an area where they are more concentrated to an area where they are less concentrated. Does not require energy, as diffusion depends on random particle movements. Molecules travel with the concentration gradiant.
What is equilibrium?
It is when the concentration of the solute is the same throughout a system.
What is osmosis?
Osmosis is the diffusion of water through a selectively permeable membrane.
What is isotonic solution?
When the solute concentration level is the same inside and outside the cell.
What is hypertonic solution?
When the solute concentration level is higher on the outside of the cell compared to the inside.
What is hypotonic solution?
When the solute concentration level is higher on the inside of the cell compared to the outside.
What is facilitated diffusion?
Facilitated diffusion helps and facilitates the diffusion of glucose across the membrane. It needs the help of protein channels that act as carriers, which makes it easier for certain molecules to cross. This process will occur only if there is a higher concentration of the particular molecule on one side than on the other side. It does not require energy. Molecules travel with the concentration gradiant.
What is Active Transport?
The active transport is when cells move materials in the opposite direction- against a concentration gradiant. Active transport requires energy. The active transport of small molecules to ions across a cell membrane is generally carried out for transport proteins or “pumps” that are found in the membrane itself.
What is phagocytosis?
Phagocytosis is also known as “cell eating.” it is when the extensions of cytoplasm surround a particle and package it within a food vacuole. The cell then engulfs it.
What is endocytosis?
Endocytosis is the process of taking material into the cell by means of infolding, or pockets, of the cell-membrane. The pocket that results breaks lose from the outer portion of the cell membrane and makes a vacuole within the cytoplasm. There are two examples of endocytosis called Phagocytosis and Pinocytosis.
What is pinocytosis?
It is when many cells take up liquid from the surrounding environment. Also known as “cell drinking.” Tiny pockets form along the cell membrane, fill it with liquid, and pinch off to form vacuoles within the cell.
What is exocytosis?
Exocytosis is when the membrane of the vacuole surrounding the material fuses with the cell membrane, forcing the contents out of the cell.
