Cells Flashcards
What’s a cell?
The smallest unit of an organism that can carry on the activities of life
What are the activities of life ?
Homeostasis: maintaining constant internal environment
Metabolism: sum of all chemical reactions needed for life
Reproduction: to make more of something
Heredity: the passing of genetic information from parent to offspring
Why are cells small?
They’re more efficient when they’re small; if cells grow too large they’re surface area becomes too small compared to the volume to take in nutrients and remove enough wastes so it won’t meet needs of cells
What will the cell do if it becomes too large ?
Divide if it can or die
Surface area and volume formula
6s(squared)
S(cubed)
What increases faster than surface area?
Volume of an object (cytoplasm) increases much faster than surface area (cell membrane)
What is mainly responsible for keeping homeostasis?
Outer surface layer of the cell known as the cell membrane
What does the cell membrane do?
Regulates the exchange of all materials; all substances that enter or leave the cell must cross the cell membrane (nutrients,wastes,information)
At what rate does the material travel if they travel further ?
Slower the greater the distance materials must travel to reach their destinations
What are the cell membrane two technical terms?
Plasma membrane: refers to ability of cell membrane to be able to move or be flexible
Bilipid layer: refers to its basic structure, 2 layers of lipid; contains phospholipids
What are the two major parts of the phospholipids ?
Head: consists of glycerol and phosphate group & has chemically polar nature
Tail: consists of 2 fatty acid chains & has chemically no polar nature (0 charge differences)
What are the membrane proteins?
2 parts that allow them to be held within phospholipid of lipid bilayer
What does the outside part of membrane protein contain?
Polar amino acids that form hydrogen bonds w/ water
What does the inside section of membrane proteins contain?
Non polar amino acids that interact w/ nonpolar Regions of lipid bilayer
What are the three types of membrane protein ?
Channels,receptors, & ID markers
What do channels do?
allow ions & some polar molecules to enter & exit the cell
What do receptors do?
Each type has unique shale & conveys information from outside the cell to inside the cell
What does the special shape of the receptor allow it to do?
Fit with only one type of molecule which then regulates the cells function
What do ID markers do?
Function with immune system to determine if cell is part of that organism or if it’s foreign invader
What are id markers codes for by?
persons DNA so identical twins will have identical markers and close family members will have some similarities in markers if determined by non self it’ll destroy white blood cells & antibodies from immune system