Biology 1010 2 Flashcards
What is a cell?
The Basic Unit of life; smallest unit of life
What was the contribution of Leeuwenhoek
One of the first people to observe single celled organisms
What was the contribution of Hooke?
coined the term “cell”
What was the contribution of Schleiden?
Said all plants are composed of cells
What was the contribution of Schwann?
Said all animals are composed of cells
What was the contribution of Brown?
First person to observe the nucleus of an atom
What was the contribution of Virchow?
Said all cells come from pre-excisting cells.
What is cell theory?
The cell is the basic unit of life and that all living organisms are made up of one or more cells
what is the plasma membrane?
All cells have one, it separates the inner contents of the cell from the outer environment and regulates the passage of molecules and ions in and out of the cell.
What is the cell wall?
Not all cells have one, ( animal cells dont). it provides structural support for the cell.
What is cytoplasm?
A semifluid protion of the cell that lies outside the nuclues and inside the plasma membrane. Also contains organelles.
What is Cytosol?
The semi-fluid portion of the cytoplasm ( does NOT have organelles)
What are Eukaryotic cells?
DO have a membrane bound nucleus, contained in animals, plants and fungi
DNA- separated from the rest of the cell inside the nucleus
What are Prokaryotic cells?
Do NOT have a membrane bound nucleus
DNA- in the nucleotide region and is in contact with the cytoplasm of the cell.
What are the characteristics of phospholipid molecules that make them suitable for forming plasma membranes?
Ideal for forming plasma membranes because they have polar heads that orient toward the watery cytoplasm on the inside of the cell.
Describe the fluid mosaic model of the plasma ( cell) membrane.
protein molecules form a shifting pattern within the fluid phospholipid bilayer cholesterol lends support to the membrane
what is the function of the extracellular matrix in animal cells?
Do not have cell walls; but they do have a plasma membrane that has protective and supportive functions.
what is the function of the extracellular matrix in plant cells?
the cell was protects the cells inside and makes sure that they dont obtain too much water, so they dont burst, and also maintains their shape
what is the function of Desmosomes/ Adhesion Junctions?
act like rivets that mechanically connect adjacent cells ( found in skin cells)
What is the function of tight junctions?
form barriers with the external environment ( found in kidneys and digestive system)
What are the functions of gap junctions?
Allow for communication between cells ( Ions and other small molecules can pass back and forth between cells) in plants are called PLASMODESMATA
What are the functions of the nucleus?
the control center of the cell, contains DNA, directs the activities of the cell.
What is the function of the nuclear envelope?
separates the contents of the nucleus from the cytoplasm
What is the function of chromatin?
the non condensed form of DNA
What is the function of ribosomes and where are they located ?
small round organelles made of protein and RNA; function in protein synthesis. found in the cytoplasm of the cell.
What is the nucleolus?
where the components of ribosomes are made
How does DNA direct protein production?
mRNA ( messenger RNAs) copies a genetic “ recipe” from a gene on DNA in the nucleus, then mRNA carries the genetic “ recipe” from the nucleus out into the cytoplasm, ribosomes then move along the length of mRNA decoding the message into a protein product
What is the structure and function of endoplasmic reticulum?
The structure is membranous flattened channels and tubular canals; functions as a transport system
Rough ER?
studded with ribosomes and functions in processing proteins
Smooth ER
lacks ribosomes and specializes in lipid synthesis molecules moving through the endoplasmic reticulum and eventually enclose in vesicles that move to the Golgi apparatus.
What is the structure and function of the Golgi apparatus?
stack of membranous saccules; functions in processing, packaging, and distributing cell products
What is the structure and function of Lybosomes?
function: Intracellular digestion
Structure: membranous vesicles containing digestive enzymes
What is the structure and function of Vacuoles?
membrane bound sacs used for storage and transport
what is a central vacuole and where is it found?
They hold a lot of water and are found in plant cells.
What is the structure and function of chloroplasts?
its a double membrane bound organelle with a 3rd membrane inside the first two, contain thylakoids stacked into grana
Function: photosynthesis
What is the structure and function of mitochondria?
structure: double-membrane bound organelle, inner membrane is folded inward to form cristate that project into the matrix.
Function: Cellular respiration and the production of ATP molequles.
What is the structure and function of cytoskeleton?
structure: network of microtubules extending throughout the cytoplasm
function: maintains cells shape and assists in movement of cell parts.
What is the structure and function of microtubules?
Structure: Cylinders of protein molecules present in the cytoplasm, cilia and flagella.
function: maintains cells shape and assists in movement of cell parts.
List the similarities and differences between flagella and cilia
Similarities: Functions in the movement of the cell
Differences: Flagella is one or a few long extensions from some cells and cilia is several short extensions from cells.
What is energy?
The capacity or ability to do work.
What are the forms of energy?
- mechanical ( kinetic)
-chemical ( potential)
-electrical - light
- heat
What kind of energy is utilized by the cells?
Chemical energy. ( as well as heat?)
Compare kinetic energy with potential energy
Kinetic energy: energy of motion
Potential energy: stored energy
Cells use energy to do what?
- generates metabolic reactions
-transports all required substances through membranes
-helps perform mechanical works, inclusive of moving muscles
Explain the 1st Law of thermodynamics
Energy can neither be created nor destroyed, only change from one form to another.
Explain the 2nd law of thermodynamics
energy transformations are not 100% efficient. There will always be some energy released as heat
What is the primary source of energy for all living organisms?
The sun.
What is entropy?
A measure of the disorganization in a system. it takes a constant supply of energy to combat entropy. heat has the most entropy because it is disorganized.
What is meant by a one way flow of energy?
sun-plants-heerbivores-carnivores-top conivores
energy cannot be recycled