L02 Flashcards
What person advanced the field of neuroscience the most?
Charles Darwin. All animals in the world (all cells in the world) have a lot in common because they all are descendants of a common ancestor
Cells are made up of atoms: _____, ______, and _____.
protons, neutrons, electrons
Most (>99.9%) of the atoms in the universe are _____ or _____.
hydrogen, helium
How old is the oldest light we can detect?
13.7 billion years old
How far is the oldest light we can detect now because of the expansion of the universe?
46 billion years away
What is ordinary matter made of?
Elements on the periodic table
How many elements are there in the periodic table?
118 elements, but only the first 94 occur naturally on Earth
The air we breathe is largely (99%) just __ and __.
N2 and O2
What is an atom?
A chemical element
When atoms bond together, they form a _____.
molecule
What does a chemical reaction refer to?
A molecule being formed, broken, or modified in some way. ex: change in the position of electrons in the molecule
What is a molecule or single atom that has an electric charge and often breaks apart in water?
An ion
What are molecules held together by ionic bonds called?
Salts
The likelihood of a chemical reaction depends on many factors. Name one.
Temperature
When was Planet earth formed?
4.5 billion years ago
What happened sometime in the first billion years of Planet Earth?
One self-replicating cellular entity emerged out of the “primordial soup”
What are the main elements of cells (life on Earth) and their percentages?
-59% Hydrogen
-24% Oxygen
-11% Carbon
-4% Nitrogen
-2% Others (phosphorus, sulfur, …)
What does CHNOPS stand for?
Carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur.
They represent the six most important chemical elements whose covalent combinations make up most biological molecules on Earth.
What are some examples of molecules we can find in cells?
Water, sugar, lipid, nucleic acid, amino acid
What molecules formed naturally on Earth prior to the first lifeform and have been found on asteroids?
Water, sugar, lipid, nucleic acid, amino acid
What are cells made up of besides water (70% of total cell mass)?
-15% Sugars (strings of sugar molecules are called carbohydrates)
-10% Lipids (cell membranes and vesicles are made of lipids)
-15% Nucleic acids
-50% Amino acids
-10% Other organic (CHNOPS) molecules
What does RNA mean?
Ribonucleic acid
Some RNA strands are _____.
self-replicating
What are phospholipids?
Strands of fat (lipid) with a phosphate cap
Lipids prefer the company of other _____, while phosphate groups prefect to interact with _____.
lipids, water
What do phospholipids form if left undisturbed?
Bilayer sheets
What do phospholipids form when shaken?
Micelles
What will micelles do under certain conditions?
Micelles will explode and reform as liposomes
The cell membrane is basically a _____.
Liposome. Diffusion through the membrane is limited. The interior is full of salt water.
___ is more stable, more durable than ___.
DNA or RNA?
DNA, RNA.Eventually DNA replaced RNA as the predominant information storage molecule for all of life
Is RNA abundant?
No. There is a greater abundance and diversity of amino acids, which canbe strung together to form molecules of all different shapes and sizes.
What are the main catalysts of life’s chemical reactions?
Protein enzymes
The prokaryotic cell is basically a _____ _____ filled with _____ (a solution of water, salt, and sugar).
cell membrane, cytoplasm
What floats in the cytoplasm of prokaryotic cells?
- Loose strands of DNA
- Ribosomes (which are made of proteins and nucleic acids)
What is the function of ribosomes?
Make proteins, which involves linking together amino acids in the order dictated by the genetic code
What are enzymes?
Proteins that catalyze chemical reactions
What are receptors?
Proteins that sense things and react accordingly
The scaffolding and roads of a cell are made of..?
proteins. They also mediate transport and storage and serve as messengers
What is different in the eukaryotic cell compared to the prokaryotic cell?
- The DNA is compacted into the nulcleus, from which it cannot escape.
- It has mitochondria, which are responsible for extracting energy from nutrients. This energy is typically stored in the molecular bonds of the molecule ATP.
How do we call a strand of compacted DNA?
A chromosome
What is a gene?
A section of DNA that encodes a specific protein.
When a gene is read, copies of it are transcribed into ___, which can leave the nucleus
RNA
Outside the nucleus, _____ translate RNA into proteins
ribosomes
What does the genome refer to?
All of the organism’s DNA. It provides the information necessary to synthesize all of the cell’s proteins.
How many protein-encoding genes do humans have in their genome?
About 20 000
There can be “alternative” ways of reading a gene, which results in protein _____ (i.e., different versions of a protein that are made from one gene).
Isoforms
How are neurons typically defined?
By where their soma is located
The cell body (or soma) is where the _____ is located.
nucleus
What is the cytoplasm?
A semi- transparent, gelatinous fluid in which organelles are suspended.
What are mitochondria?
Semi autonomous double membrane-bound organelles. They generate ATP (the cell’s main source of chemical energy), and so are known to be the “powerhouse of the cell”.
What is the cell membrane made of?
It’s made of lipids and is embedded with proteins that have special functions. It also defines the boundary of the cell.
What do microtubules allow?
They allow for rapid transport of material throughout the neuron
How long ago did animals appear?
650 million years ago.
Once multicellular organisms formed, cells began to _____, and the structure and function of life became almost limitless.
specialize
Nerve cells haven’t changed that much in the last hundreds of millions of years. So, to understand how human neurons work, you can study a _____.
squid
What was the 1963 Nobel Prize awarded for?
Describing how neurons transmit electrical signals (i.e. the action potential) using a squid
What was the 2000 Nobel Prize awarded for?
Describing the neuronal basis of learning and memory. This was done on a sea slug
What is the percentage of the mammalians alive today that are rodents?
40%
What is the percentage of the mammalians alive today that are bats?
20%
_____ are evolutionarily closer to humans than cats, dogs, bats, sloths, elephants, etc.
Rodents
Because of the genetic and behavioral similarities between humans and _____, as well as their small size, _____ have become the dominant group of species used in neurobiology research.
rodents!
What 3 species are our closest living relatives — the only present-day hominids (humanlike apes) besides ourselves?
Chimpanzees, gorillas, and orangutans. DNA analysis shows that genetically there is very little difference between humans and these 3 species.
Humans and chimpanzees share ___ % of their DNA.
98.8
When does the production of new neurons almost ceases?
At birth. But the neurons that are already present grow and establish connections with each other, and other types of brain cells, which protect and support neurons, begin to proliferate. After birth, the human brain continues to grow larger and heavier in a dramatic fashion.
When does the human brain reach its adult size?
Late adolescence
What does an adult size human brain weight?
1400g - about 4x the weight of a newborn’s brain
How many estimated planets are there in the Milky Way that could support life?
40 billion
How old is the Milky Way galaxy?
Over 13 billion years old
How much time would it take to colonize the Milky Way galaxy if interstellar travel was possible?
5 to 50 million years
How many galaxies are estimated to be in our observable universe?
2 trillion galaxies
What is the Fermi paradox?
The Fermi paradox is the conflict between the lack of clear, obvious evidence for extraterrestrial life and the various high estimates for their existence.
