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In this cheat sheet with the main topics of Biology: Scientific Method, Water & its Properties, Macromolecules, cell structures, genetics, and so on
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Substances with a pH below 7 are called Acids. Substances with a pH above 7 are called Bases. Substances with a pH of 7 are Neutral. Water is the only neutral substance. The pH scale actually measures the amount of HYDROGEN IONS (H+) that are present in a solution. pH could stand for “ THE POWER OF HYDROGEN .” The lower the pH value, the greater the amount of hydrogen ions (H+) present in the solution
Step 1: Make an OBSERVATION. The two types are: → QUALITATIVE: Descriptions without number. (Ex) The book is heavy. → QUANITATIVE: Descriptions that use numbers. (Ex) The book has 250 pages. Step 2: Make a HYPOTHESIS. This is an educated guess based on qualitative and quantitative data. ⇒ Scientist should look for 2 variables in trying to find answers to the problem. ◊ INDEPENDENT VARIABLE (IV) The thing I change ◊ DEPENDENT VARIABLE (DV) The thing I measure Step 3: Setup a CONTROLLED EXPERIMENT. Each has:
axis is the DV. The thing I measure X axis is the IV. The thing I change
The chemical formula of water is H 2 O. It has 2 hydrogen and 1 oxygen. Water has a positive side (hydrogen) and a negative side (oxygen). These charges allow water to stick to other things that also have a charge. HYDROGEN BONDS hold water to itself and to other charged substances. When water sticks to other things (like a car window) ADHESION is taking place. When water sticks to itself COHESION is taking place Water comes in 3 states: solid, liquid or gas. In the solid state (ice), water is less dense than the liquid state. Ice floats! Water has a HIGH SPECIFIC HEAT. It can absorb a lot of energy without increasing its own temperature. This is why water takes so long to boil! We use this property to help us regulate our body temperature. When our body temperature gets too high, we start to PERSPIRE (sweat).
Macromolecules
Macromolecules
Enzymes are CATALYSTS. Catalysts SPEED things up! Without enzymes, chemical reactions (metabolism) would happen too slowly to keep you alive. Enzymes are shape specific. Enzymes can only catalyze reactants ( Substrates) if they can fit inside the enzyme’s ACTIVE SITE. Enzymes speed up chemical reactions by LOWERING ACTIVATION ENERGY. Activation energy is the amount of energy needed to start a chemical reaction. Activation Energy works like a speed bump.
Enzymes
Transport
There are two types of transport: PASSIVE & ACTIVE
There are 3 types of PASSIVE Transport:
CELLULAR RESPIRATION is a process that turns sugar ( glucose C 6 H 12 O 6 ) into usable energy for the cell ( ATP ). HETEROTROPHS (organisms who cannot make their own food) use this process to release ATP from food in the MITOCHONDRIA. INPUT (Reactants) : Mitochondria take in oxygen and glucose OUTPUTS (Products) : Mitochondria release carbon dioxide and ATP!!!! PHOTOSYNTHESIS is a process that turns light energy from the sun into food ( glucose ) for plants. Plants and organisms that make their own food are called AUTOTROPHS. Autotrophs perform photosynthesis in their CHLOROPLASTS. INPUT (Reactants) : Chloroplasts take in carbon dioxide and sunlight. OUTPUTS (Products) : Chloroplasts release oxygen and glucose.
DNA
When DNA needs to divide, DNA REPLICATION begins. The weak hydrogen bonds that are holding the two strands of DNA together break apart and the DNA “unzips.” The two original strands of DNA then become templates for new daughter strands of DNA that will form.
DNA
Frst, DNA is turned into MESSENGER RNA (mRNA). RNA is the skinny cousin of DNA which means it can leave the nucleus. RNA is single‐stranded. It one strand looks almost identical to DNA with the exception of the nitrogen base URACIL. Uracil takes the place of thymine., so U pairs with A. ♦ Making RNA from DNA is called TRANSCRIPTION. Next, the message transferred from DNA to mRNA makes it way to the ribosome (the site of protein synthesis). ♦ Making proteins from mRNA is called TRANSLATION. Cell Division
Genetics
There are two types of alleles: ‐ DOMINANT ALLELES: The expressed trait. Represented by a capital letter. ‐ RECESSIVE ALLELES: The unexpressed trait. Represented by a lowercase letter. The two letters (representing two alleles) represent an organism’s GENOTYPE. There are two types of genotypes: ‐ HOMOZYGOUS : two identical alleles (TT) or (tt) ‐ HETEROZYGOUS : two different alleles (Tt) The expression of the genotype (physical appearance of the gene) is the PHENOTYPE. We can use the parent genotypes to predict what offspring might look like. Monohybrid crosses can be completed by using a PUNNET SQUARE.
Example of a monohybrid cross: Consider a cross between a true breeding tall plant (TT) and a true breeding short plant (tt).