Lesson 2: Cell biology Flashcards
What is stuff made of?
All ordinary matter in the universe is made of atoms
- atoms are made of protons, neutrons, and electrons
What happens when a molecule is created, broken apart, or modified?
A chemical reaction
- these reactions often just involve a change in the position of electrons in the molecule
What does the likelihood of a chemical reaction depend on?
The temperature
- the shape of the molecule will determine the chemical reaction: pushing apart or together
What is an ion?
When a molecule or single atom has an electric charge
- ions form ionic (electric) bonds with each other
What are molecules that are held together by ionic bonds called?
Salts
- ionic bonds typically break apart (dissolve) in water
What are the characteristics of the mitochondria and what does it do?
It has 2 membranes, has its own DNA, copies its DNA and splits, etc.
- it converts sugar to the ATP molecule
What type of cell started evolution on Earth?
Eukaryotic cells
- they formed multicellular organisms, forming the structure and function of life (animals)
What are the 6 main elements of cells (of life on Earth)?
Carbon
Hydrogen
Nitrogen
Oxygen
Phosphorus
Sulfur
What are the 5 components of the cells? (CHNOPS elements combinations)
- Water
- Sugar
- Fat (lipid)
- Nucelic acid
- Amino acid
T/F: Amino acids make up 50% of a cell
True. Long strings of amino acids are called proteins
- 15% sugar (carbohydrates)
- 10% fat (lipid)
- 15% nucleic acids (RNA & DNA)
- 10% other organic molecules
What is RNA?
Refers to a type of nucleic acid, specifically a ribonucleic acid
- some strands of RNA can catalyze chemical reactions: it is then called a ribozyme
What is it called when a strand of RNA can catalyze a chemical reaction?
A ribozyme
What is it called when a protein can catalyze a chemical reaction?
An enzyme
What are tRNAs?
Small strands of RNA that can hold an amino acid, which can be easily strung together to make new proteins
What is a ribosome? What is its function?
A molecular machine. It creates new proteins by linking together the amino acids held by tRNA molecules
- function: stringing together the amino acids held by tRNA in the order dictated by the genetic code, thus creating proteins
How does the ribosome make new proteins?
They synthesize new proteins by translating long strands of RNA
- they slide across long strands of RNA, taking one step every time they find a tRNA molecule that complements the section of the long RNA strand
- when a ribosome finds one of these tRNA molecules, it removes its amino acid and attaches it to the amino acid of the next complementary tRNA molecule
- step by step, the ribosome links together the amino acids held by tRNA molecules
Why are proteins so important in all of life?
Protein enzymes became the main catalyst of life’s chemical reactions
Why is DNA so important?
RNA breaks apart easily. DNA is much better for long term information story
- more stable and durable than RNA
What is a phospholipid bilayer?
Strands of fat (lipid) with a phosphate cap
- lipids prefer the company of other lipids, while phosphate caps prefer to interact with water
What are the steps to the chemical reactions of life?
- All the instructions of life are stored in strands of DNA
- Sections of DNA are transcrived into strands of RNA
- RNA strands are translated into chains of amino acids called proteins
- Protein enzymes catalyze the chemical reactions of life
When shaken, what do phospholipids form?
Micelles (soap bubbles), which can pop and reform as liposomes
What are liposomes?
The cell membrane is basically a liposome
- diffusion through the membrane is limited. The interior is full of salt water
What is the prokaryotic cell?
Basically a cell membrane filled with cytoplasm (a solution of water, salt, and sugar)
What floats in the cytoplasm?
- Very long, loose strands of DNA
- Shorter loose strands of RNA
- Ribosomes (which are made of strands of RNA and strands of amino acids)
What are proteins? What are their function?
They are the enzyme that catalyze the chemical reactions of life
- the structure and roads of a cell are made of proteins
- function: mediate transport and storage & serve as messengers
What is the nucleus? Where is it found?
Imprisons the cell’s long strands of DNA
- the strands of DNA inside the nucleus are called chromosomes and they are never allowed to leave the nucleus
- it is found in the cell body (soma)
What is the difference between the eukaryotic cell and the prokaryotic cell?
Eukaryotic cell: contains membrane-bound organelles which are the basis of unicellular and multicellular organisms
Prokaryotic cell: always part of unicellular organisms (do NOT have organelles)
What does the genome provide to the cell?
The information necessary to synthesize all the cell’s proteins
What happens when a gene is read (the genome being transcribed into RNA and translated into proteins which are genes)?
The segment of DNA is transcribed into RNA. RNA is allowed to leave the nucleus, and after it leaves, ribosomes traslate RNA to create proteins
What are genes?
Sections of the genome that get transcribed into RNA and translated into proteins
- a section of DNA that codes for a specific protein
What are the proteins that are made from a single gene called?
Protein isoforms
What are mitochondria?
Semi-autonomous doule membrane-bound organelles
- known as the powerhouse of the cell because they generate ATP, the cell’s main source of chemical energy
What allows for rapid transport of material throughout the neuron?
Microtubules
Which person advanced the field of neuroscience the most?
Charles Darwin
T/F: 40% of mammalian species alive today are rodents
True.
- rodents are evolutionarily closer to humans than cats & dogs
Why do we experience on rodents even if we don’t like killing animals? (3)
- Human illnesses are real and we want to heal them
- The ends justify the means (justifying torturing animals to advance science)
- Students believe it’s the best way to advance science
T/F: Humans and chimpanzees share 98.8% of their DNA
True
- our genomes are very similar to the great apes alive today (chimpanzees, gorillas, and orangutans)
How many times does the weight of a newborn brain increase by adolescence?
Four times
T/F: Neurons continue to grow and establish new connections with other neurons throughout life
True. And other types of brain cells, which protect and support neurons, continue to replicate
- neoteny: prolongation of maturation
