Unit 5 - Biology Flashcards
(34 cards)
Cell Theory
- All living things are made up of +1 cells
- Cells are basic unit of life
- Cells come from pre-existing cells
Prokaryote
- Cell doesn’t contain nucleus or membrane-bound organelles.
- Bacteria and archaea
- Tens to thousands of times smaller than eukaryotes
Eukaryote
- Cell that contains nucleus and other organelles surrounded by thin membrane
- Protists, fungi, animals, and plants
Organelle
Cell structure that performs specific function for cell
Cytoplasm
- Suspends all organelles in cell and moves them around
- Mostly water, other substances cell stores until needed
- Chemical reactions take place, changing it from jelly-like to liquid
Cell Membrane
- Flexible double-layered organelle surrounding cell
- Allows some substances (ex: water, oxygen) to enter, keeps others (ex: proteins) out
- “Semi-permeable membrane”
Nucleus
- Roughly spherical structure containing genetic information controlling cell activities
- Stores info in chromosomes containing deoxyribonucleic acid, or coded instructions
- DNA copied when cell divides so new cell has complete DNA
Mitochondria (s: mitochondrion)
- Cells store energy as glucose.
- Mitochondria contains enzymes converting stored energy for use (known as cellular respiration - requires oxygen)
Active vs. Passive Cells
Active cells (muscles) have more mitochondria than others (fat-storage - may have 1-2 only) as they need faster cellular respiration
Endoplasmic reticulum
- 3D branching tubes and pockets extending through cytoplasm and from nucleus to cell membrane
- Fluid-filled tubes transport material through cell
Golgi bodies
- Collect materials to be removed from cell
- Make and secrete mucus.
- Cells that secrete lot of mucus (ex: cells lining intestine) have many Golgi bodies.
Vacuole
- Single layer of membrane enclosing fluid in sac.
- Containing substances, removing unwanted substances from cell, maintaining internal fluid pressure (turgor) within the cell.
Animal vs. Plant Vacuoles
- Animal cells have small vacuoles not visible.
- Mature plant cells have one central vacuole visible under microscope.
Plant: Cell Wall
- Outside cell membrane.
- Rigid but porous structure made of cellulose.
- Holds long after plant died.
Large Vacuole
- Vacuole takes most space inside cell.
- When full of water, turgor pressure keeps cells plump, keeping plant’s stems firm.
- If water level drops, vacuoles lose turgor pressure and cells become soft
Chloroplast
- Plant cells exposed to light have chloroplasts
- Contain chlorophyll, absorbing light energy used in photosynthesis
Asexual Reproduction
- Producing offspring from one parent cell
- Offspring is genetically identical to parent, receiving complete set of genetics
Sexual Reproduction Details
- Parent cells typically have half of DNA in regular cell
- Half-cells known as “gametes”
Cell Division
- Allows organisms to reproduce, grow and repair damage
- Used by all cells to reproduce
Sexual Reproduction Process
- Producing offspring by fusion of two gametes
- Offspring has genetics from each parent
Meiosis
Additional cell division process production of gametes entails
Diffusion
- Transport for moving chemicals into and out of cell from area of higher concentration to that of lower concentration
- Chemicals enter cell across membrane to cell
Osmosis
Movement of fluid across membrane toward area of high concentration
Reason for Size of Cells
- Chemicals must be available to all parts of cell, in right amount of water
- Waste products must diffuse out of cell quickly
- Chemicals and water cannot move through large cells fast enough.