Biology Chp 2 Flashcards
Chapter 2
What is a eukaryote?
A cell that contains a nucleus and other organelles that are surrounded by a thin membrane.
**CAN BE A SINGLE-CELLED OR MULTICELLULAR ORGANISIM
What are stem cells?
Stem cells are unspecialized cells that do not have a function yet.
- find their purpose as the organism grows
- make up characteristics suited to their role
- CAN become anything
- can’t reverse after specializing
Where is DNA found?
In the nucleus
Describe what happens in prophase
Chromosomes coil, condense, and thicken enough to become visible.
Because DNA was copied in interphase, you see sister chromatids. They are held on by centromeres.
The nuclear membrane breaks down and disappears
Centrosomes head to two opposite sides of the cell and Spindle Fibers form from them.
What happens in Cytokinesis?
The cell membrane begins to punch and the cell finally divides into two daughter cells!
What are the 4 phases of mitosis?
Prophase, Metaphase, Anaphase and Telophase
What is diffusion?
The movement of particles from an area of high concentration to a low concentration until all the particles are evenly distributed.
What is the cell theory?
- All living things are made up of one or more cells.
- The cell is the simplest unit of life that carries out all processes.
- All cells only come from other cells.
Cytoplasm
jelly-like substance that fills the cell and surrounds other organelles. Protects organelles and provides nutrients.
Name the two types of stem cells
- Embryonic Stem cells
- Adult Stem cells
Cell Wall
A rigid frame around the cell that provides strength and protection. Only found in plant cells
Cell Membrane
Double lipid layer that protects the cell and allows substances to move in/out.
Describe an embryonic stem cell
Embryonic stem cells are found in the embryo and can be harvested from the umbilical cord.
Why do checkpoints occur during interphase?
Checkpoints occur during interphase to stop cell division incase:
- there is not enough nutrients for cell growth
- the DNA in the nucleus has not been replicated
- the DNA is damaged
What is osmosis?
The movement of water molecules across a semi-permeable membrane to even out concentration.
What are the three phases in interphase and their function?
G1: A growth period where new organelles and proteins are made
Synthesis: Cell synthesizes a copy of the DNA to prepare for mitosis
G2: Continuing to prepare for mitosis
Describe what happens in metaphase
Chromosomes (or sister chromatids) line up in the middle of the cell.
Spindle Fibers stretch out from the centrosomes to the centromeres of each chromosome.
What is a prokaryote?
A cell that does not contain a nucleus or other membrane-bound organelles.
Vacuoles/Vesicles:
Membrane-bound organelle that stores nutrients, waste, and other substances the cell uses.
Nucleus
Control center of the cell that contains all of the cell’s DNA.
What are the three stages of cell division?
- Interphase
- Mitosis
- Cytokinesis
Describe an adult stem cell
Adult stem cells can also specialize but are more limited in what they can become.
Found in TISSUES and ORGANS.
Role: maintain and repair the tissue where they are found.
Describe what happens in telophase
The spindle fibers disappear
A nuclear membrane forms around the two daughter chromosomes
Cell now has 2 nuclei
Daughter chromosomes uncoil and stretch enough to become invisible again.
Three reasons for cell division
1/ Growth
2/ Repair
3/ Reproduction
Describe what happens in anaphase
Centromeres split apart forming two sets of chromatids.
Spindle Fibers pull the chromatids to the opposite sides of the cell.
The two sets of chromosomes are now referred to as daughter chromosomes.
What is concentration?
the number of molecules of a substance in a given volume.
Can be high concentration or low concentration.
Chloroplasts
Contains a green substance called chlorophyll. Chlorophyll uses energy from the sun to convert CO2 and H20 into sugar and oxygen. (Photosynthesis)
PLANT CELL ONLY
How many pairs of chromosomes do Humans have?
23
Differences between Plant and Animal cells.
- Animal cells do not contain chlorophyll and chloroplasts BUT plant cells do.
- Animal cells do not have a cell wall, plant cells do.
- Animal cells store energy in carbohydrates or lipids and plant cells store them in the form of starch or oils.
Lysosomes
Digestion area of the cell. Break down bacteria and also clean up.
What are organelles?
“Organs” of a eukaryotic cell that perform specific functions.
Golgi apparatus (or Golgi bodies)
receives proteins from the endoplasmic reticulum and packages those proteins for delivery throughout the cell.
Full form of DNA
deoxy-ribo-nucleic-acid
Mitochondria
The powerhouse of the cell! Supplies the cell with energy.
Endoplasmic reticulum - what are the two kinds?
Organelle is made up of small tubes that carry materials throughout the cell.
ROUGH ER: Use small ribosomes to make proteins.
SMOOTH ER: Makes fats and oils and does not have ribosomes.