Outline the cell theory
cells are the unit of structure & function in living things
- living organisms are composed of cells
- cells are the smallest unit of life
- cells come from preexisting cells
Define unicellular
organisms made up of one cell but still carry out all the functions of life (metabolism, homeostasis, growth, reproduction, etc)
Define multicellular
organisms made up of many cells, where individual cells are specialized for one particular function
stem cell
cells that retain their ability to divide & differentiate into carious cell types
surface area to volume ratio
limits cell size to ensure there is enough surface area for gas exchange, supply of nutrients, and removal of waste between cells
cell wall
tough and slightly elastic; made of cellulose and present only in plant cells
Pili
structure on cells that enables attachment to surfaces and other bacteria
Nucleoid
a singular, circular chromosome of DNA in the cytoplasm, attached to the plasma membrane
hydrophilic
water-loving
osmosis
diffusion of water molecules across a partially permeable membrane from a region of high water concentration to a region of lower water concentration
active transport
uptake of substances against a concentration gradient from an area of low concentration to high concentration. requires ATP energy input and is also called a "pump
protein pump
used for active transport across membrane with the use of ATP
mitochondria
organelle in eukaryotic cells where ATP is made through cellular respiration
rough endoplasmic reticulum
site in eukaryotic cells where protein synthesis of proteins that will be exported from cells occurs
Prokaryote
cells smaller than eukaryotes. lack membrane bound nucleus & organelles. single circular chromosome of DNA known as naked DNA. contain ribosomes and divide by binary fission.
plasma membrane
made of a phospholipid bilayer with proteins floating within the phospholipids. purpose is to isolate the cell's contents from the external environment, regulate exchange of essential substances between cell & environment, and communicate with other cells
Flagella
used for movement in prokaryotic cells
fluid mosaic model
illustrates the cell (plasma) membrane.
Phospholipids
make up double layer of plasma membrane & responsible for isolating functions of the membranes with its hydrophilic head & hydrophobic tail
facilitated diffusion
movement across the membrane down the concentration gradient with the help of a channel or carrier protein
Exocytosis
transport of large materials through the membrane and out of the cell
Nucleus
control center of eukaryotic cells, contains DNA & is surrounded by the nuclear envelope
Golgi apparatus
stacks of flattened membranous sacs that function in sorting, classifying, and modifying proteins
smooth endoplasmic reticulum
produces phospholipids, steroids, fatty acids, & detoxifying chemicals in eukaryotes
Eukaryotic
cell found in animals. has a nucleus & organelles such as ribosomes, smooth er and rough er, golgi apparatus, lysosomes, centrioles, etc.
Cytoplasm
site of chemical reactions of life in cells
Ribosomes
site of protein synthesis - manufacture proteins
Hydrophobic
water hating
Diffusion
net movement of molecules down a concentration gradient from regions of high concentration to low
Endocytosis
intake of large materials across plasma membrane & breaks off material into a large sac called a vesicle
Vesicle
membranous sac formed by phospholipids during endocytosis
Nucleolus
inside nucleus, where rRNA is made and where ribosomes are put together
Lysosome
small sacs of digestive enzymes that break down complex molecules
Chloroplast
found only in plant cells, filled with chlorophyll & is the site of photosynthesis
Discuss evidence for the cell theory
Some evidence that supports the cell theory is that unicellular organisms are made of one cell but still carry out all the functions of life. Also, no spontaneous generation of cells forms from nonliving matter.
Compare the relative sizes of molecules, cell membrane thickness, viruses, bacteria, organelles, and cells using the appropriate SI units
Molecules are 1 nm. Thickness of cell membrane is 10 nm. Viruses are 100 nm. Bacteria are 1 um. Organelles are up to 10 um. Most cells measure up to 100 um.
Explain the significance of the surface area to volume ratio as a factor limiting cell size
the surface area to volume ratio should stay relatively low in order to keep a lower surface area for gas exchange, supplying of nutrients, and removal of waste from the cell.
What is meant by stating that multicellular organisms show emergent properties?
Stating that multicellular organisms have emergent properties means that it has properties that in total are greater than the sum of all its individual parts - the system is greater than all its components.
What are stem cells? Why are they useful for therapeutic treatments of different disorders?
1. Stem cells are cells that retain their ability to differentiate & divide into various cell types. They are useful for treatments of disorders because they are flexible and can grow into any type of mature cell, even cells that can replace damaged cells
Outline one therapeutic use for stem cells.
one use of stem cells is for treatment of patients with Alzheimer's or Parkinson's diseases. Stem cells are used to replace damaged cells within the body
Compare & contrast prokaryotic and eukaryotic cells
Prokaryotic cells lack a nucleus and membrane-bound organelles
Compare & contrast plant & animal cells
1. Animal cells do not have chloroplasts or a cell wall. Also, in plant cells there is usually one large, central vacuole, while in animals there are many smaller ones.
Outline two roles of the extracellular matrix
The extracellular matrix is home to glycolproteins, formed by animal cells for support, adhesion, and movement and also to the cell wall, made of cellulose & helps maintain shape in plants
Explain how the hydrophobic and hydrophilic properties of phospholipids help to maintain the structure of cell membranes
Cell membrane structure is maintained because the hydrophobic tails always want to be away from water and the hydrophilic heads want to be around water. As a result, the phospholipids arrange themselves into a bilayer with the tails on the inside and the
Describe how the fluidity of the membrane allows it to change shape, break, and re-form during exocytosis & endocytosis
Due to the structure of the membrane, it is flexible enough to change shape, break vesicles, and reform vesicles during exocytosis and endocytosis. To do this, vesicles fuse with the membrane & in endocytosis, materials are absorbed and encased in a vesic