Cell biology Flashcards
What is stuff made of?
- All ordinary matter in the universe is made of atoms
What are atoms made of?
- protons, neutrons, electrons
What are the simplest atoms?
- hydrogen and helium
How much of the universe is made up of hydrogen and helium?
- more than 99%
When was the big bang?
- 13.7 billion years ago
When did atoms form?
- 380 000 years after the big bang
- when the universe had cooled enough for electrons to stably associate with protons and neutrons
When did Earth form?
- 4.5 billion years ago
What are the most basic chemical elements?
- the atoms on the periodic table
How do we identity atoms?
- atomic number (number of protons)
How many elements naturally occur on Earth?
- 94
What is a covalent bond?
- sharing of electrons
- do not break apart in water
What is a molecule?
- two or more atoms connected with covalent bonds
What is a chemical reaction?
- when a molecule is created, broken apart, or modified
- change in the position of electrons in the molecule
- change how molecules interact with other molecules
What is an ion?
- atom or molecule has a net electrical charge (positive or negative)
- missing or extra electron
What is an ionic bond?
- Negatively charged ions can donate an electron to positively charged ions
- break apart in water
What are salts?
- atoms and molecules connected with ionic bonds
- dissolve in water
Do water molecules or ionic bonds neutralize electrical charges better?
- water molecules
What are the 6 key chemical elements whose combination make up most of the biological molecules on Earth?
- hydrogen (59%)
- oxygen (24%)
- carbon (11%)
- nitrogen (4%)
- phosphorus
- sulfur
What are the 5 main molecules found in cells?
- water
- sugar
- fat (lipid)
- nucleotide
- amino acid
What are macro-molecules?
- chains of small molecules
- big molecules
What are carbohydrates made of?
- chains of sugar molecules
- macro molecules
What do lipid molecules form?
- cell membranes and vesicles
- macro molecules
What are nucleic acids made of?
- chains of nucleotides
- RNA and DNA are types of nucleic acids
- macro molecules
What are proteins made of?
- long chains of amino acids
- between 100 and 1000 amino acids long
- macro molecule
What are peptides made of?
- short chains of amino acids
- macro molecule
What is RNA?
- a ribonucleic acid
- naturally fold into complex 3-dimensional shapes
- some can catalyze chemical reactions