(Unit 4) Ch. 4 Flashcards
What is the important emergent property within cells?
Life; it only exists when biomolecules and chemistry are organized into a cell.
Define “Cell”
Smallest unit of living matter
What is Cell Theory?
- All organisms are composed of ONE OR MORE cells (accounts for unicellular organisms)
- Cells are the basic units of structure and function (and therefore life) in organisms (no spontaneous generation)
- Cells come only from pre-existing cells because cells are self-reproducing
Describe the basic difference in reproduction/growth between single-celled organisms and multicellular organisms.
Single Cell- Reproduces- Divides and becomes two new organisms
Multicellular- Grows- Many cells divide
What do all cells have that allow them to support Life? How are they related?
Structure and Function- Structure allows for function and function requires structure
According to FCPS, what are the Characteristics of Life?
HOG RACER (+D) maintain Homeostasis highly Organized Grow and Develop Reproduce Adapt and Evolve made of Cells obtain and use Energy Respond to environmental stimuli
Have DNA (may change in future)
What is the difference between Growth and Development?
Growth- Get’s bigger (refers to size)
Develop- Changing in organization
What is Homeostasis and what is it an example of?
Example of response to environmental stimuli and it means it maintains a constant internal environment despite external conditions
What is organization in relationship to the characteristics of Life?
How things work together either in a cell (unicellular) or between each other (multicellular)
Distinguish the difference between (genetic) adaptation and evolution.
Adapt- genetic adaptations; ex: beak size
Evolution- Driven by adaptation
Clarify how cells respond to environmental stimuli.
Must stay within the zone of tolerance; ex: homeostasis
Are viruses alive?
Controversial issue, scientists still are unsure.
Why are cells so small?
- Rate of Diffusion
- Surface area to Volume Ratio
- Amount of DNA
Explain how the rate of diffusion affects cell size.
- The further something is, the longer it takes to defuse
- If the distance is to great within the cell, the cell runs risk of running out of ATP at further distances
- If substances take to long to diffuse, it could lose homeostasis (and therefore die)
Explain how the surface-area-to-volume ratio affects cell size.
- surface determines how much membrane is available to allow substances in and out of the cell (nutrients to enter and wastes to be eliminated)
- volume determines how much cytoplasm there is to use nutrients and to make wastes (essentially metabolism)
- needs surface area to be big enough, smaller cells have larger ratio
- if ratio is to small, cell could lose homeostasis
What is metabolism? Give and describe two examples of metabolism.
Metabolism- All chemical reactions happening in an organism
Catabolic metabolism- extracting chemical energy fro biomolecules (cellular respiration)
Anabolic metabolism- building new biomolecules (dehydration synthesis)
Explain how the amount of DNA affects cell size and how cells can bypass this limitation.
- bigger the cell, the more “parts” it will need and therefore it will need more DNA
- Cells can get around this limitation through genetic duplication and (in the case of some very large protists) have multiple nuclei
Define Endocytosis and Exocytosis.
Endocytosis: Enters the Cell
Exocytosis: Exits the Cell
What are the two different types of cells that exist in nature and what are there differences?
Prokaryotic Cells: Lack a membrane-bound nucleus
Eukaryotic Cells: Possess a nucleus
What domain do Prokaryotes and Eukaryotes belong?
Prokaryotes- Eubacteria and Archaea
Eukaryotes- Eukarya
Compare and Contrast Prokaryotes and Eukaryotes.
- Prokaryotes are structurally less complicated
- Prokaryotes metabolic capabilities as a group exceed those of eukaryotes
- Eukarotes have multiple chromosomes but prokaryotes have a single, coiled chromosomes
- Both have a plasma membrane that separates contents of cell from the environment and regulates the passage of molecules in and out of cytoplasm
How is bacteria present within society and the ecosystem?
- Can cause serious diseases
- Decompose remains of dead organisms
- Contribute to ecological cycles
- Used to manufacture products (industrial chemicals, foodstuffs, drugs (diabetes))
What is the average size of Prokaryotes?
1.1 - 1.5µ wide and 2.0 - 6.0µ long
Name and describe the basic shapes of prokaryotes.
Bacillus: Rod-shaped bacterium (Can occur as pairs or chains)
Coccus: Spherical-shaped bacterium (Can occur as pairs, chains or clusters)
Spirilla: Rigid, long rods twisted into spirals
Spirochetes: Flexible, long rods twisted into spirals
Describe the general organization of bacteria.
Cell Envelope, Cytoplasm, and External Structures
Name the different components of the Cell Envelope.
Plasma Membrane, Cell Wall, Glycocalyx
Describe and state the function of Plasma Membrane.
Phospholipid bilayer with embedded proteins which regulates the entrance and exit of substances into and out of the cytoplasm in order to maintain its normal composition
N.B. In prokaryotes- can form internal pouches called mesosomes which increase the internal surface area for the attachment of enzymes that carry out metabolic activities
Describe and state the function of the Cell Wall.
Maintains the shape of the cell
Contains peptidoglycan, a complex molecule containing a unique amino disaccharide and peptide fragments
Describe and state the function of Clycocalyx
Layer of polysaccharides that lies outside the cell wall in some bacteria
Also called a capsule when the layer is well organized and not easily washed off
“Slime” layer is easily removed
Helps resist a host’s immune system, aids against drying out, and helps bacteria attach to almost any surface
What is cytoplasm?
Semifluid solution composed of water and inorganic and organic molecules (which include enzymes which speed the chemical reactions in metabolism) encased by a plasma membrane