Chapter 3 Flashcards
What is a cell?
the basic unit of structure and function in organisms
Who discovered cells and when
Robert Hooke; 1665
What is cell theory?
- All organisms are made up of one or more cells
- Cells are the basic unit of structure and function of all organisms
- All cells come from other cells that already exist
Who invented the complex microscope
Antony van Leeuwenhoek
What are the two types of cells
prokaryotic and eukaryotic
what are prokaryotic cells
cells without a nucleus or membrane-bound organelles
What are eukaryotic cells
cells with a nucleus and membrane-bound organelles
Are all cells the same shape and size?
no
why do cells come in different shapes and sizes
different tissues contain cells with different sizes and shapes for functional purposes
What is a ligand?
A molecule that specifically binds to a receptor protein on a cell’s plasma membrane
what are examples of ligands
hormones, neurotransmitters, nutrients, enzymes, ions, antibodies
What are the main structures of a cell
plasma membrane (cell membrane)
nucleus
cytoplasm/organelles
What is the function of the plasma membrane
- protection (serves as a barrier from the outside of the cell)
- semi-permeable/selectively permeable (allows only certain molecules to enter or exit)
- communication (allows cells to talk to their surroundings)
What is the composition of the plasma membrane?
- lipids (phospholipids)(cell membrane)
- proteins (cell membrane)
- Carbohydrate chains
- some cholesterol
What do the phospholipid molecules in the plasma membrane do?
- double layer that acts as a barrier for the cell
- allows oxygen, carbon dioxide, steriods to enter and exit but few other molecules can get through this layer
What are the 3 cell surface proteins
marker proteins, channel proteins, and receptor proteins
What do marker proteins do?
identify the cell
What do channel proteins do?
allows specific molecules to enter and exit
What do receptor proteins do?
allows cells to communicate
What is the name given to cell surface proteins that extend through the lipid bilayer and may protrude from one or both sides of the cell membrane
integral protein
What is cytoplasm
the area inside the cell surrounding the nucleus
What is found inside the cytoplasm of the cell?
organelles
What fluid is found in the cytoplasm of the cell?
cytosol
How is the nuclear membrane similar to the cell membrane
they look the same and have the same composition
What does the nucleus contain?
DNA
Nucleolus (produces ribosomes)
The nucleus is enclosed by _____
the nuclear membrane
What does the nuclear membrane do
acts just like the plasma membrane of the cell
What is the composition of the nuclear membrane
- lipids (phospholipids)
- proteins
- Carbohydrate chains
- some cholesterol
What are the two ways in which molecules can enter and exit through the plasma membrane?
active transport and passive transport
What is passive transport
- no energy is used by the cell
- used to get things in and out of the membrane
- diffusion, osmosis, facilitated diffusion, filtration
WHat is active transport?
- cell’s energy must be used (40%)
- endocytosis and exocytosis
What are the four types of passive transport systems?
diffusion, osmosis, facilitated diffusion, filtration
Which passive transport systems require a concentration gradient of high to low?
diffusion, osmosis, facilitated diffusion
How did molecules enter and exit through the plasma membrane?
passive and active transport
What is it called when molecules move from an area of high concentration to one of a low concentration through a cell’s membrane
diffusion
What is it called when molecules
of water move from an area of high concentration to one of a low concentration through a cell’s membrane
osmosis
What specific molecules in the human body enter and exit through diffusion?
oxygen, carbon dioxide, and steroids
How does osmosis differ from diffusion
- water instead of other molecules
- water moves through the pores in the membrane not directly through the phospholipid bilayer
When molecules are too large to enter or exit by normal means and instead have to enter or exit through special carrier proteins
facilitated diffision
Facilitated diffusion is how ___ and ___ enter the cell
glucose and some ions
Molecules are forced from regions of higher pressure to regions of lower pressure
filtration
Does filtration have to be from high concentration to low concentration?
no
What is an example of filtration
water leaving capillaries
What are the two types of active transport systems?
endocytosis and exocytosis
The movement of molecules in through the plasma membrane, usually too large to enter any other way
Endocytosis
What are the types of endocytosis
Pinocytosis
Phagocytosis
Receptor-mediated endocytosis
What is pinocytosis
fluids entering in through the plasma membrane
What is phagocytosis
solids (molecules like proteins and carbohydrates) entering in through the plasma membrane
The movement of moolecules out of the plasma membrane, that are usually too large to exit by itself
exocytosis
What is the definition of the cell cycle?
The life span/cycle of a cell. (The stages of a cell’s life.)
The series of changes that a cell undergoes, from the time it forms until it divides.
What organelle forms ribosomes?
nucleolus
What organelle houses the genetic information (DNA)
nucleus
What organelle surrounds the nucleus?
nuclear membrane/envelope
What organelle provides structural support and enzymatic activity to link amino acids to synthesize proteins
ribosomes
What organelle forms the cytoskeleton
microtubules and microfilaments
What organelle is part of the centrosomes, cilia and flagella?
microtubules and microfilaments
What organelle forms bundles and provides cell motility?
microfilament
which is bigger: microfilament or microtubules
microtubules
What organelle moves fluids such as mucus over the surface of certain tissies
cillia
What organelle contains centrioles and microtubules?
centrosome
What organelle is the genetic information?
chromatin
What organelle refines, packages, and transports proteins synthesized on ribosomes associated with the ER
golgi apparatus
What organelle is primarily in the cytoplasm of liver and kidney cells
proxisomes
What organelle moves in a wave, which begins at its base, that allows the cell to “swim”
flagella
What organelle stores or transports distances within a cell between cells
vesicles
What organelle extracts energy from the nutrients in digested food? Where is it located?
mitochondria; cytoplasm
What organelle digests waste materials and cellular debrais using enzymes? It also recycles damaged organelles and helps defend against pathogens. Where is it located?
lysosomes; cytoplasm near the ER and golgi apparatus
What organelle stores excess water and food?
vacuoles (plants only)
What organelle can identify and dismantle misfolded proteins?
Endoplasmic reticulum
What organelle is a thread-like strand?
microtubules, and microfilaments
What organelle provides structural support and enzymatic activity to link amino acids to synthesize proteins?
ribosomes
What organelle has nuclear pores that allow certain molecules to exit the nucleus?
nuclear membrane/envelope
What organelle maintains the acidic pH that enables the enzymes to function and shield the rest of the cell from the acidic conditions?
lysosomes
What organelle transports molecules from one cell part to another
Endoplasmic reticulum
What organelle houses enzymes and catalyzes a variety of biochemical reactions
peroxisomes
What organelle (sometimes) has receptors that detect molecules that signal sensations to cells
(these organelles on cells deep in the nasal cavity assist in the sense of smell)
cillia
What 5 characteristics do cancers share and their meaning
hyperplasia - uncontrolled cell division
dedifferentiation - loss of specialized structures and functions of cell
invasiveness - ability of cancer cells to break through boundaries (basement membranes)
angiogenesis - induce extension of nearby blood vessels
metastasis - spread of cancer cells to other tissues through the bloodstream
what does the restriction checkpoint do
determines cells fate
whether it will continue to divide, become specialized, or die
what may cause cell division
stimulation from a hormone or growth factor
do all cells divide?
no; nerve cells do not divide
what cells need telomerase in order to stay long
bone marrow
when do chromosomes become visible
prophase
What is mitosis
division of the nucleus
What happens at prophase?
chromosomes become visible
centrioles move to opposite poles
nuclear membrane and nucleolus disappear
spindle fibers spread out
What happens at metaphase?
chromosomes line up in the middle of the nucleus and attach to a spindle fiber
What happens at anaphase
centromeres are pulled apart and chromatids become individual chromosomes
What happens at telophase
nuclear envelope forms as well as nucleolus
chromatid becomes chromatin
what is the definition of meiosis
process that separates the chromosomes in the nucleus of a germ cell, resulting in the production of four genetically different haploid nuclei
