Chapter 1 - Cells And More Cells Flashcards
(28 cards)
Who discovered cells?
Robert Hooke in 1665
The cell theory
- All living organisms are made of one or more cell
- The cell is the basic organizational unit of life
- All cells come from pre-existing cells
What are proteins for
Essential nutrients for growth and repair of body tissues
Cell membrane
Separates inside of cell from outside, controls flow of materials
Mitochondria
Where energy is released from glucose to fuel cell activities
Ribosomes
Help produce proteins, some float in cytoplasm, others are attached to endoplasmic reticulum
Endoplasmic reticulum
Network of membrane covered channels that transport materials made in cell, connected to nucleus
Vesicles
Membrane covered sacs transport/store materials inside cell, sometimes help materials enter/exit cell
Golgi body
Sorts/packages proteins and other molecules for transport out of cells
Vacuoles
Contain water and other materials, used to store/transport small molecules
Cytoskeleton
Filaments and tubules provide framework for cell, maintain structure, lay tracks for vesicles and organelles to move along
Cell wall
Tough, rigid structure lying outside cell membrane providing structure for cell
Chloroplasts
Trap energy from sun to make glucose, broken down in mitochondria
Differences in plants and animal cells
1) Plants have 1 large vacuole, animals have several smaller
2) plants have a cell wall
3) plants have chloroplasts
Why do we breathe oxygen
Cellular respiration requires oxygen to break down glucose molecules to release energy
What are chromosomes
Chromosomes are made up of DNA, master set of instructions determines what cell becomes, how it functions, how long it lives.
What can a mutation do
Mutation in a gene can alter structure of protein produced, affects how well the protein does its job
Examples of mutagens
Electromagnetic radiation (x rays, UV rays), Mercury
How can mutations help
May help organism adapt to environment (eg. Bacteria resisting antibiotics)
Three reasons cells divide
- To repair lost or damaged cells
- So an organism can grow
- Reproduction
Why do all genes need to be replicated
Genes determine what proteins are produced, every cell needs to have all of the genes required to make proteins
What happens during DNA replication
Each chromosome is duplicated, the two copies (sister chromatids) remain attached. If errors occur, usually detected by special proteins. Centrosome also doubles, they help to organize tubules that will make up cytoskeleton
What are chromosomes normally like
Very long loose threads, then chromosomes take on thick bulging look just before ready to divide
What happens during prophase
Replicated chromosomes condense, membrane of nucleus breaks down, nucleolus, centrosomes head towards opposite ends, spindle fibres begin to form and extend towards centromeres and away from centrosomes
