Chapter 7- Cell Structure and Function Flashcards
Who is Robert Hooke?
In 1665, he looked at a thin slice of cork and coined the term cells. 1st part of cell theory: cells are basic unit of life
Who was Matthias Schleiden?
German botanist;concluded that all plants are made of cells
Who was Theodor Schwann?
German biologist; all animals were made of cells
Who was Rudolf Virchow?
German physician; concluded that new cells could be produced only from the division of existing cells
What are the 3 parts of the cell theory?
1) cells are the basic units of structure and function in living things
2) all living things are made up of cells
3) new cells are produced from existing cells
What is the nucleus of a cell?
a large membrane-enclosed structure that contains the cell’s genetic material in the form of DNA; it controls many of the cell’s activities
What are eukaryotes?
cells that contain nuclei where their genetic material is separated from the rest of the cell
What are prokaryotes?
cells that don’t contain nuclei
What are two things that eukaryotes and prokaryotes both have?
cytoplasm and cell membrane
What are organelles?
little organs within the cell
What is the cytoplasm?
jellylike substance outside of nucleus but enclosed by the cell membrane; where all organelles are found
What is the cell membrane?
thin flexible barrier made of a lipid bilayer that surrounds cells
What is the purpose of the cytoplasm?
give cell its shape
What is a lipid bilayer in the cell membrane?
2 layers of lipid with proteins embedded and CHO chains attached to the proteins
What are the functions of the cell membrane?
1) regulates what comes in & out of cell
2) protection
3) support
What is the cell wall?
- rigid layer outside of cell membrane
- made of CHOs and protein
- found only in plant cells
What is the purpose of the cell wall?
to provide support and protection to the cell
What is the nucleolus?
Small dense region inside the nucleus
What is the function of the nucleolus?
to make ribosomes
What is chromatin?
granular material that consists of DNA; found in the nucleus
What happens to chromatin as the cell divides?
it condenses to form chromosomes
What is a chromosome?
thread-like structures that contain genetic info
What is the mitochondria?
peanut shaped organelle enclosed by 2 membranes; only inherited from mother
What is the function of the mitochondria?
converts the chemical energy stored in food into compounds that the cell can use for energy
What is the golgi apparatus or complex?
stacks of membranes closely packed together
What is the purpose of the golgi complex?
to modify, sort, and package proteins and other materials from ER for storage in the cell or for secretion out of the cell (postal service)
What is a ribosome?
a small particle of RNA and protein; found throughout cytoplasm or attached to rough ER
What is the function of the ribosome?
to make protein
What is the Smooth Endoplasmic Reticulum?
internal membrane system without ribosomes; contains enzymes
What is the function of the smooth ER?
make lipids; transport materials inside cell
What is the rough endoplasmic reticulum?
internal membrane system with ribosomes attached; surrounds the nucleus
What is the function of the rough ER?
synthesis of proteins from ribosomes
What is the centriole?
located near the nucleus; made of microtubules; only found in animal cells
What is the purpose of the centriole?
help with cell division (mitosis and meiosis)
What is the cytoskeleton?
network of protein filaments; made of microfilaments and microtubules
What is the function of the cytoskeleton?
help support the cell; maintain its shape; help materials move within the cell
What is the lysosome?
small organelle filled with enzymes; found only in animal cells
What are the functions of the lysosome?
eat/break down lipids, CHO, and proteins; remove junk from cell; break down old organelles
What is a chloroplast?
large stacks of membranes; double membrane; found only in plant cells
What is the function of the chloroplast?
capture energy from sunlight and convert it into high energy sugars; photosynthesis
What is a vacuole?
storage saclike structures; large central vacuole is found in plant cells only
What is the function of the vacuole?
store water, food, salts, CHOs. proteins, and wastes
What is the contractile vacuole? Functions?
specialized vacuole that pumps excess water out of cells; helps maintain homeostasis
What is the concentration of a solution?
the mass solute in a given volume of solution or mass/volume
What is diffusion?
the process by which molecules of a substance move from areas of higher concentration to areas of lower concentration
Does diffusion require energy?
no
What is osmosis?
diffusion of water through a selectively permeable membrane
What does it mean when a membrane is semipermeable or selectively permeable?
some substances can pass across them and other can’t
What is equilibrium?
when concentration of the solute is the same throughout a system
What is isotonic?
concentration of solutes is the same inside and outside of the cell (water in, water out)
What is hypertonic?
solution has a higher solute concentration than the cell (water out)
What is hypotonic?
solution has a lower solute concentration than the cell (water in)
What happens during facilitated diffusion?
molecules such as glucose that cannot diffuse across the cell membrane’s lipid bilayer on their own move through protein channels instead
What is the function of the CHO in the cell membrane?
chemical identification cards, so cells can communicate with each other
What is active transport?
when cells need to move materials against a concentration difference; requires energy
How do small molecules or ions transport across a membrane during active transport?
transport protein pumps that are found in membrane
How do larger molecules and clumps of material be actively transported?
endocytosis and exocytosis
What is endocytosis?
the process of taking material into the cell by means of infoldings or pockets of the cell membrane
What is phagocytosis?
cell eating; extensions of cytoplasm surround a particle and package it within a food vacuole; amoebas do this
What is pinocytosis?
form of taking in liquid
What is exocytosis?
membrane of vacuole surrounding material fuses with cell membrane, forcing the contents out of cell; removal of water is carried out by contractile vacuole
What is cell specialization?
when different cells develop to perform different tasks in a body
What is a stem cell?
A cell that hasn’t specialized yet
What are the levels of organization in a multicellular organism?
individual cells, tissues, organs, organ systems, organism