Science Flashcards
what is cell theory?
- All living things are made up of one or more cells and their products
- The cell is the simplest unit that can carry out all life processes
- All cells come from other cells; they do not come from non-living matter
Prokaryotic cells
No nucleus or membrane bound organelles (e.g. bacteria)
Very simple and small
Organisms are single-celled
Eukaryotic cells
Has a nucleus and other organelles, each surrounded by a thin membrane (e.g. plant & animal cells)
Cells have a more complex organization than prokaryotes
Organelles exist to perform a specific function within a cell
Can be single-celled or multicellular organisms
what are the 2 kingdoms of prokaryotic cells
Archaea
Bacteria
what are the 4 kingdoms of Eukaryotic cells
Protists (unicellular)
Fungi
Plants
Animals
characteristics of living things
Movement
Respiration
Sensitivity
Growth
Reproduction
Excretion
Nutrition
what is an organelle?
An organelle is a cell structure that performs a specific function for the cell
cytoplasm
Jelly-like substance that fills cells
All the organelles in the cell are suspended in the cytoplasm
Allows for cell reactions to occur
cell membrane
Supports the cell
Double layered
Allows some substances to enter while keeping others out of the cell
Referred to as semi-permeable membrane
nucleus
- Control centre of the cell
- Has a semi-permeable membrane known as the nucleus membrane
- Contains genetic information that controls all cell activities
- Contains DNA/Chromatin
nucleolus
Area inside the nucleus where ribosomes are made
mitochondria
- The “powerhouse” of the cell
- Makes energy available to the cells
- Sugars are converted into usable energy (ATP)
- Cite of cellular respiration
endoplasmic reticulum
- Network of tubes that runs through the cytoplasm from the nuclear membrane to the cell membrane
- Used for transporting material and proteins
- In the brain the ER assists with the production of hormones
- In the muscles the ER is involved with muscle contraction
- Involved in protein and lipid synthesis
what is usually attached to the ER
ribosomes
what are the 2 types of ER and what is the difference?
Smooth ER: no ribosomes
Rough ER: has ribosomes
golgi bodies
- Collect and process materials to be removed from the cell
- Makes and secrete mucus
- It modifies proteins and lipids (fats) that have been built in the ER and prepares them for export outside of the cell or for transport to other locations in the cell
vacuoles
- A single layer of membrane enclosing fluid in a sac
- The functions of vacuoles vary greatly
- These include storage of food or wastes of water, removing waste from cell or maintaining cell pressure
what is the difference between plant and animal cell’s vacuoles?
Animal cells: small vacuoles
Plant cells: one large central vacuole
cell wall
Located just outside the cell membrane; provides support and protection for the cell
do both animal and plant cells have a cell wall?
only plant cells
chloroplasts
- Contain chlorophyll and give leaves their green colour
- Absorb light energy
- Site of photosynthesis
do both animal and plant cells have chloroplasts?
only plant cells
photosynthesis
Carbon Dioxide + Water + Energy (sunlight) → Glucose and Oxygen
CO2 + H2O + Energy –> C6H12O6 + O2
ribosomes
- Where proteins are assembled
- exist in the cytoplasm as well as attached to the outer surface of the rough endoplasmic reticulum (RER)
- non-membrane bound organelle
centrioles
Create spindle fibres which are required for cell division
do both animal and plant cells have centrioles?
only animal cells
lysosomes
- The garbage can of the cell - contains digestive enzymes to help break down materials and eliminate waste
- If the cell is damaged beyond repair, lysosomes can help it to self-destruct in a process called programmed cell death, or apoptosis
mostly in animal cells
plant cell shape and size
- 10-100 micrometers in length
- Typically rectangular or cubic in shape
animal cell shape and size
- 10-30 micrometers in length
- Typically round or irregular
what do all cells need?
- Source of energy
- Nutrients
- Water
- Gases
diffusion
A transport mechanism for moving chemicals into and out of the cell, from an area of higher concentration to an area of lower concentration
concentration
The number of substance (solute) present in a given volume of solution
Concentration (C) = solute/solvent
solute
what is being dissolved
solvent
what is dissolving the solute
solution
result of solute dissolved into solvent
osmosis
The movement of a fluid (water), across a membrane from an area of higher concentration to lower concentration
why do cells divide
- Reproduction
- Growth
- Repair
why do cells cycle?
- Do not last forever
- Must grow
- Must produce new cells themselves
- Must repair themselves
why do cells die?
- Age
- Redundancy
- Unable to function
- Damaged
sexual reproduction
- producing offspring from two parents; the offspring inherits genetic information from each parent
- Eukaryotic cells contain half the genetic information from two individuals combine to form offspring
plasmid
small secondary strand of genetics (DNA)
meiosis
Produces genetically different offspring
asexual reproduction
Mitosis
- Single celled organisms divided to create two “daughter” cells
- Produces identical offspring
what are the phases of the cell cycle?
- Interphase
- Mitosis
- Prophase
- Metaphase
- Anaphase
- Telophase
- Cytokinesis
what is the longest phase in the cell cycle?
interphase
what happens in the interphase?
Cells perform their functions and prepare for mitosis
what are the 3 subphases of interphase?
G1 (gap 1)
S (synthesis)
G2 (gap 2)
what happens in G1?
Cell undergoes normal activities and grows
what happens in S?
Replication of DNA (chromatin); cell continues to grow
- DNA must be replicated before cell division
- Each new cell will have an identical copy of DNA
- Semi-conservative = each cell has half of the old/original DNA and half new DNA
what happens in G2?
Growth preparation for mitosis usually shortest phase
what is G0?
- “resting state”
- cells stay either temporarily (until cell is ready to divide) or permanently
what happens in mitosis?
Process of cell division that ensures each new cell gets a complete (identical) copy of the genome
what are the phases of mitosis?
prophase
metaphase
anaphase
telophase
