Biology Flashcards
What are the 3 stages of the cell cycle?
Interphase
Mitosis
Cytokinesis
What happens during interphase?
During interphase the cell carries out all life activities except division
What do the DNA material look like?
Very long invisible strands
When the cells prepare for division in interphase, what happens to the DNA strands?
The strands are duplicated and more organelles are formed.
What is mitosis?
The division of the contents of the nucleus (DNA)
What is cytokinesis?
The division of the rest of the cell (ie. cytoplasm etc.) each cell division produces 2 genetically identical cells called daughter cells.
What are the 4 phases of mitosis?
Prophase
Metaphase
Anaphase
Telophase
What happens in prophase?
- Copied DNA strands condense into visible chromosomes
- the 2 identical DNA strands (chromatids) are held together by a centromere
- nuclear membrane dissolves, nucleus disappears
- centrioles move to opposite ends of the cell forming spindle fibres between them
What happens in metaphase?
Chromosomes line up along the middle of the cell and attach to spindle fibres by the centromere
What is anaphase?
Centromere splits and the sister chromatids separate (now called “daughter chromosomes”)
Spindle fibres retract pulling the two daughter chromosomes to opposite ends of the cell
What is telophase?
Chromosomes reach opposite poles of the cell and start to unwind to become less visible
-spindle fibres break down and new nuclear membranes form
What happens in cytokinesis?
Division of cytoplasm to complete the creation of two new daughter cells
- an indentation forms and pinches the cell into two cells
- daughter cells are genetically identical
- in plant cells a cell plate forms between the daughter cells that will form a new cell wall
- in animal cells the cell membrane and cytoplasm pinch inward (forming a cleavage furrow) at the middle separating the two cells
Give an example of an individual cell
A heart muscle cell
What are the levels of cell organization within each organism?
- An individual cell
- Tissue
- Organs
- Organ systems
What is tissue?
A group of similar cells that share the same structure and function
What are the 4 major types of tissue in animals?
Epithelial
Connective
Muscle
Nerve
What is an organ?
- A combination of several types of tissue working together to preform a certain function
- has connective, nerve and muscle tissue
- most organs are only involved in one function (ex. Pancreas -> digestion and also the endocrine (hormonal) system)
What is an organ system?
A group of organs working together to preform a vital body function ex. circulatory system (heart, blood vessels, blood)
-some systems are interconnected ex. circulatory, respiratory and urinary
What is an organism?
All the organ systems working together to allow a plant or animal to carry out life functions
What are the 2 types of stem cells?
Embryonic and tissue
What is an embryonic stem cell?
Can differentiate into any kind of cell
-found in very young embryos (less than a week old)
What are the 3 principals of cell theory?
- All living things are made of cells
- The cell is the simplest unit of all life
- All cells come from other cells
What are prokaryotes?
- the simplest cells
- lack a nucleus and other advanced cell parts
- single felled bacteria are considered a prokaryotic cell
What are eukaryotes?
- eukaryotic cells can exist as single celled organisms or multi cellular organisms
- have more complex internal organization including a nucleus etc.
- protists, fungi, plants and animals have eukaryotic cells
What is muscle?
Made up of long cells that are able to contract.
What is nerve?
Cells are long and thin with a long axon
What is the digestive tract?
Lined with epithelial tissue (like skin) and has many goblets, cells to produce mucus, to allow for the smooth transport of food and protection from digestive enzymes
What is the mouth?
Breaks down food mechanically with the use of teeth and tongue and chemically using enzymes to break large molecules to smaller ones