Lecture 2: Intro to Biological Systems Flashcards
Who advanced the field of behavioural neuroscience the most?
Charles Darwin (evolution)
T or F: All animals in the world are descendants of a common ancestor.
True
Atoms consist of
protons, neutrons, and electrons
Most (>99.9%) of the atoms in the universe are
hydrogen and helium
When were protons, neutrons, electrons and atoms formed?
We think protons and neutrons and electrons were formed seconds after the big bang.
But it took thousands of years for the Earth to cool down enough to make atoms
Looking in any direction, the oldest light we can detect is
13.7 billion years old.
The area of space where the oldest light originated from is now ____
46 billion light years away
Atom
a chemical element
Molecule
Atoms bonded together
how many elements have been identified?
118
how many elements are found naturally on Earth?
94
The air we breathe is largely (99%)
N2 & O2
chemical reaction
A molecule being formed, broken, or modified in some way
T or F: Living entities (cells) regulate chemical reactions to grow, accomplish things, and manipulate their environment
T
Ions
A molecule or single atom that has an electric charge
Ionic bonds
Bonds formed by electrically charged ions
Salts
Molecules held together by ionic bonds
T or F: Ionic bonds often break apart (dissolve) in water
T
The main elements of cells are:
59% Hydrogen (H, the element with 1 proton)
24% Oxygen (O, the element with 8 protons)
11% Carbon (C, the element with 6 protons)
4% Nitrogen (N, the element with 7 protons)
2% Others (phosphorus, sulfur, …)
CHNOPS
carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur, represents the six most important chemical elements whose covalent combinations make up most biological molecules on Earth.
T or F: CHNOPS elements primarily exist alone
False; Primarily in the form of molecules (rarely exist in the cell alone)
Basic molecules of life
Water
Sugar
Lipid
Nucleic acid
Amino acid
most abudant molecule of life
water
T or F: All basic molecules of life formed naturally on Earth before the first lifeform
T
the basic molecules of life are found in
chain-link structures
How much of the cell mass does water make up?
70%
Besides water, what are cells made up of?
15% Sugars
10% Lipids
15% Nucleic acids
10% Other organic (CHNOPS) molecules
Carbohydrates
Strings of sugar molecules
cell membranes and vesicles are made of
lipids
nucleic acids example
strings of DNA & RNA
RNA
- a self-replicating strand of nucleic acid.
- can catalyze chemical reactions
- some think it was the first self-replicating entity
Phospholipids
strands of fat (lipid) with a phosphate cap
Phospholipid Bilayer
Thin membrane that doesn’t allow things that dissolve in water to cross
RNA vs. DNA
DNA is less fragile and abundant so it overtook RNA as the primary means of information storage
Protein enzymes vs. RNA
RNA- based enzymes probably started incorporating proteins in them and eventually, protein enzymes began to replace RNA enzymes as the main catalyst of life’s chemical reactions
cytoplasm
a solution of water, salt, and sugar in which organelles are suspended
DNA
strings of nucleic acids
Ribosomes
- made of proteins and nucleic acids
- function: make proteins, which involves linking together amino acids in the order dictated by the genetic code.
prokaryotic cell
- Formed within the 1st billion years
- Basically, a cell membrane filled with the cytoplasm, and ribosomes and DNA floating around
proteins
Strings of amino acids that do things in cells (mediate transport and storage and serve as messengers)
enzymes
proteins that catalyze chemical reactions
receptors
proteins that sense things and react accordingly
chromosome
A strand of compacted DNA
mitochondria
semi-autonomous double membrane-bound organelles. They generate ATP, the cell’s main source of chemical energy
Lysosomes
“garbage machines” that contain digestive enzymes
eukaryotic cell
- appeared ~2 billion years after the prokaryotic cell
- similar but has DNA compacted into the nucleus & mitochondria
Gene
a section (functional unit) of a chromosome. It is a section of DNA that encodes a specific protein
Ribosomes
translate RNA into proteins
genome
all of a cell/organism’s DNA. Provides the information necessary to synthesize all of the cell’s proteins.
how many genes are in the human genome?
20,000
isoforms
different versions of a protein that are made from one gene
soma
Where the nucleus is located
how are neurons defined?
based on where their soma is
Cell membrane
defines the boundary of the cell. It consists of lipids and is embedded with proteins that have special functions
microtubules
allow for rapid transport of material throughout the neuron
Evolution of multi-cellular organisms
- Earth was formed 4.5 billion years ago
- Sometime in the first billion years, one self-replicating cellular entity emerged
- Sometime in the next 2 billion years eukaryotic cells formed
- We think a big bacteria ate a smaller one which created a eukaryotic cell
- Collections of eukaryotic cells came together to form multicellular organisms
- Once multicellular organisms formed, cells began to specialize and the structure and function of life became almost limitless
When did nerve cells evolve?
around 600 million years ago
When did animals first appear?
around 650 million years ago
Studying neurons
Neurons haven’t changed much in the last 600 million years, so we can study the neurons of other animals (ex. rodents)
Why are rodents ideal test subjects?
- Rodents are evolutionarily closer to humans than cats, dogs, bats, etc.
- small size
- we find it unethical to use other primates because of how genetically similar they are to humans
The debate on animal research in behavioural neuroscience
is it ethical to torture animals if it means coming closer to understanding human neurological processes?
closest living relatives of humans
other hominids: chimpanzees, gorillas, and orangutans
most similar: chimpanzees (98% of shared DNA)
why are humans smarter than other hominids?
- After birth, the human brain continues to grow larger and heavier
- Production of new neurons almost ceases at birth, but those 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
when does the human brain reach its adult size?
late adolescence
what is the adult size of the human brain?
1400 g
how much larger is an adult brain than a newborn’s
4 times
the femi paradox
Within our galaxy, there are estimated to be about 40 billion planets that could support life. So, where is everybody?
how are proteins created?
- transcription (DNA to RNA)
- translation (RNA to protein)
neoteny
extended youth of the human brain
