What is a cell?
Smallest, most basic unit of living organisms (“fundamental unit of life”)
–>From unicellular to multicellular, all organisms are made up of cells -
–>Smallest unit of life that preserves the properties of life (growth, reproduction, and metabolism) - capable of carrying out essential life processes
What are the properties of a cell?
- Vary greatly in size and shape, but contain similar properties
- Ability to store and transmit (reproduce)information (stable archive of information that encodes and determines physical attributes (DNA))
- Plasma membrane that separates living material within the cell from nonliving environment around it
- Ability to harness energy from environment
What is DNA?
→ Double-stranded helix (each strand made up of sequence of 4 different molecules (nitrogenous bases)
→ It’s the arrangement of these subunits that encode cellular information
Info encoded in DNA –directs→ form proteins*
What is the difference between transcription and translation?
- Existing proteins create a copy of the DNA’s information → “create mRNA (transcription: DNA → mRNA)
- Specialized molecular structures within the cell read mRNA and determine which building blocks (amino acids) to use to create a protein (translation: mRNA → proteins)
What is a gene and what is a mutation?
Gene: specific segment of DNA that encodes a specific protein
Mutation: mistakes in DNA replication that cause diversity or evolution, but could also be lethal
What is the central dogma?
Pathway from DNA to mRNA; describes basic flow of information in a cell
What is the difference between cytoplasm and cytosol?
Cytoplasm: within the cell, but outside the nucleus; content other than the nucleus
Cytosol: jelly-like internal environment that surrounds the organelles
What are the structural properties of prokaryotes and eukaryotes?
What is metabolism?
Chemical reactions by which cells convert energy from one form to another as they build and break down molecules
–>Sugars store energy in their chemical bonds (break down sugar → cells harness their energy → convert usable form for the body (ATP)
What are the 3 principles that compose the cell theory?
- All organisms are made up of cells
- Cell is the fundamental unit of life
- Cells come from preexisting cells
What is a virus? Why aren’t these considered smallest units of life?
Agents that infects cells
→ They do have a stable archive of genetic information (RNA or DNA)
→ Such genetic archive is surrounded by a protein coat
→ CANNOT harness energy from the environment = can’t read and use information contained in their genetic material, nor can regulate the passage of substances across the protein coat (THAT’S WHY THEY REQUIRE A CELL’S MACHINERY TO REPLICATE)
What are the steps underlying a viral infection?
- Virus infects a cell by binding to cell’s surface
- Inserting genetic material into the cell
- Uses cellular machinery to produce more of itself
- Once done using the cell → virus can lyse/break the cell and enable new viruses to seel out and infect more cells (some cases, genetic material of virus becomes integrated into the DNA of the host cell)
What is the main difference regarding genetic material between prokaryotes and eukaryotes?
Prokaryotes: non-defined nucleus
Eukaryotes: defined nucleus
What are some of the characteristics that ALL cells share?
- Plasma membrane
- Genetic material
- Cytoplasm
- Ribosomes
What is the difference in size between prokaryotes and eukaryotes?
What is the difference in DNA expression between prokaryotes and eukaryotes?
What is the difference between between the mechanisms underlying gene diversity in prokaryotes and eukaryotes?
How do single-celled eukaryotes normally reproduce?
Asexually by “mitotic cell division”
- Right conditions, 2 cells may fuse and form a diploid (zygote → zygote formed by single-celled eukaryotes functions as a resting cell)
Zygote forms
Covers itself with protective wall and lies dormant until environmental conditions improve
Signals from environment induce meiotic cell division = 4 genetically distinct haploid cells
- Some single-celled eukaryotes normally exist as diploid cells
Reproduce asexually (mitotic division = more diploid cells)
Become smaller with each asexual division
Critica size reached → triggers meiotic cell division = haploid gametes that fuse to generate diploid
How does enthalpy and entropy affect the stability of a reaction?
How does enthalpy and entropy affect free energ
What is the difference between spontaneous and non spontaneous reactions?
“ If it is spontaneous then energy has been released, but ir energy input is required to drive something forward, then its non-spontaneous”
→ Energetically favourable process = spontaneous (reaction moves from less stable to more stable and is likely to happen in this direction)
→ Energetically unfavourable process = non spontaneous (moves from more stable to less stale, requires energy input to happen in this direction)
What is free energy?
Amount of work that a system can generate
Available potential energy
→ Change in free energy is referred to as the change in system energy when enthalpy and entropy are combined
