Biology Test 3 Flashcards
Chapters: 11, 12, 13, 14, 15 (37 cards)
Cells most often communicate with each other via _________.
Chemical signals
For short distances, cells communicate using __________.
Local Regulators - Messenger molecules that only travel a short distance.
For long distance, cells communicate using _____.
Homones
Reception is:
The chemical reactions that result in a special protein (an “active protein”) Only cells with the right receptors respond to specific chemical signals Most receptors are plasma membrane proteins called a Ligand (fits like a lock-and-key into the receptor molecule)
Transduction is:
A series of chemical reactions that result in a special protein. (an “active protein”)
Response is:
The active protein triggers a cellular response
A receptor that acts like a gate when the receptor changes shape:
A Ligand-gated ion channel - when a signal molecule binds as a ligand to the receptor, the gate allows specific ions through the channel in the receptor.
Apoptosis is:
Programmed or controlled cell suicide. Components are chopped up and packaged into vesicles that are digested by scavenger cells. Prevents enzymes from leaking out of a dying cell and damaging neighboring cells.
Steriods are:
Hydrophobic lipids. Sex hormones are steroids they send their signals by binding to “intracellular receptors”
Cell division is:
When one cell becomes two. The most important part of cell division is copying the cell’s DNA
A cell without DNA is a ____________
dead cell
In a unicellular organism, a division of one cell ____________________________.
Reproduces the entire organism
In multicellular organisms, division of one or more cells _______________________,
Does not reproduce the entire organism, just specific cell types.
Cell division is used for:
- Growth - body size increases 2. Development - going through stages, developing new organs, tissues, etc. 3. Repair - Tissue renewal
Mitosis is:
Cell division that creates two “daughter” cells with exactly the same DNA as the “parent” cell
Meiosis is:
Cell division that creates sperm cells and egg cells. The sperm cells created by meiosis does NOT have exactly the same DNA as one another, and neither do the egg cells created
A genome is:
All the DNA in a cell constiutes the cells genome.
DNA is packed into chromosomes
Somatic cells:
(nonreproductive cells) have TWO sets of chromosomes
Gametes:
(Reproductive cells: sperm and eggs) have half as many chromosomes as somatic cells.
This is because half come from mom and half come from dad, then they come together and make a full set
Mitosis only occurs in ____________, not ___________.
somatic cells, not Gametes
Eukaryotic Cell division consists of ______ and ______
and what do they mean?
Mitosis, the division of the genetic mterial in the nucleus
Cytokinesis, the division of the cytoplasm
What are the stages of the cell cycle?
- Interphase - Cell growth and copying of chromosomes in preparation for cell division. The DNA copies are joined together at the centromere. These are called sister cromatids.
- Prophase - The cromosome becomes visable under a microscope, and the miotic spindle builds.
- Metaphase - The nucleus is gone. The chromosomes line up in the middle of the cell. Microtubules start to attach themselves to the chromosomes.
- Anaphase - The miotic spindle pulls the sister chromotids apart, and they go to the opposite end of the cell.
- Telophase - The cell splits in two. Each new cell has two complete sets of chromosomes.
What is the metaphase plate?
the chromosomes line up in the middle of the cell, along an imaginary line called the metaphase plate.
two examples of gametes
three examples of somatic cells
eggs and sperm cells
skin, organ, blood… anything but eggs and sperm cells.
