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Biology Cheat Sheet: Main Topics, Cheat Sheet of Biology

In this cheat sheet with the main topics of Biology: Scientific Method, Water & its Properties, Macromolecules, cell structures, genetics, and so on

Typology: Cheat Sheet

2019/2020

Uploaded on 10/23/2020

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Substances*with*a*p H*below*7*are*called *Acids.*Substances*w ith*a*pH*above*7*ar e*called*Bases.*Subs tances*with*a*pH*of*7*are*Neutral.**Water*is*
the*only*neutral*sub stance.*
*
The*pH*scale*actuall y*measures*the*amou nt*of*HYDROGEN5IO NS5(H+)5that*are*pr esent*in*a*solution.*pH*could*stand*for*“T HE$POWER$OF$
HYDROGEN.”**The$lower*the*pH *value,*the*greater*the*amou nt*of*hydrogen*ions*(H+)*present*in*the*solution5
*
You$CAN$Pass$Your$Biology$SOL!$
Scientific Method
Step$1:$Make*an*OB SERVATION.**The*tw o*
***************types*are:*
*
$QUALITATIVE:$$Des criptions**
* *****without*number.*(Ex)*The**
******book*is*heavy.*
$QUANITATIVE:$Descriptions**
*** *****that*use*numbers.*(Ex)*The**
* *****book*has*250$pages.*
*
Step$2:$Make*a*HYP OTHESIS.$$This*is*an **
***************educated*guess*based*on**
***************qualitative*a nd*quantitative*dat a.*
*
****Scientist*should*look*for*2**
*********variables*in*try ing*to*find**
*********answers*to*the*problem.*
*
*INDEPENDENT$VAR IABLE$(IV)$
$$$$$$OThe*thing*I*change*
$DEPENDENT$VARIA BLE$(DV)$
$$$$$$OThe*thing*I*measure$
*
$
Step$3:$Setup*a*CON TROLLED$$
$$$$$$$$$$$$$$$EXPERIMENT.**Each*has:*
**
1. CONTROL$GROUP:$t he*group*
that*stays*the*same*( doesn’t*
receive*the*IV).**It’s*n eeded*to*
compare.*
*
2. EXPERIMENTAL$GROUP:$the*
group*that*is*manipulated*(the*
group*you*are*performing*the*
experiment*on).**This*group*
receives*the*IV.*
*
Step$4:*Make*a*CON CLUSION*or*THEOR Y$
$
If*the*data*gathered*from*your**
*****controlled*experiment*support*
*****your*hypothesis,*y ou*accept*
*****your*conclusion.*
If*the*data*doesn’t*su pport**
*****your*hypothesis,*s tart*over!*
How$to$Identify$Variables$on$
a$Graph:$
*****Scientists*use*the$SCIENTIFIC$METHOD$to*help*them*answer*questions*and*solve*problems*about*the*natural*world.******
*
*
*
………………………………………………………………………….*
*
………………………………………………………………………….*
YOaxis$is$the$DV.$
The$thing$I$measur e$
XOaxis$is$the$IV.$
The$thing$I$change$
*Water*makes*life*possible!**It’s*a*universal*solvent,*comes*in*three*states,*and*has*a*high*specific*heat*to*regulate*temperature**
*
The*chemical*formula*of*water*is*H2O.$$It*
has*2*hydrogen*and*1*oxygen.*
$
$
$
$
$
$
$
$
$
$
$
*
*
Water*has*a*positive *side*(hydrogen)*and *a*
negative*side*(oxyge n).***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)*ADHES ION*is*taking*place.*
*
When*water*sticks*to*itself*COHESION*is*
taking*place*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
**
$
Water*comes*in*3*sta tes:*solid,*liquid*or*
gas.**In*the*solid*stat e*(ice),*water*is*less*
dense*than*the*liquid*state.**Ice*floats!*
*
Water*has*a*HIGH$SPECIFIC$HEAT.**It*ca n*
absorb*a*lot*of*energ y*without*increasing*
its*own*temperature .**This*is*why*water*
takes*so*long*to*boil !*
*
We*use*this*property *to*help*us*
regulate*our*body*te mperature.**
When*our*body*temperature*gets*
too*high,*we*start*to*PERSPIRE*
(sweat).***
*
We*do*not*want*our*body*temperature*
to*fluctuate*very*much*because*it*
would*alter*chemical*reactions*
(METABOLISM).*When*
metabolism*is*thrown*off,*
HOMEOSTASIS$(balance)*is*also*
thrown*off.*This*can*lead*to*death!!!!*
$
Water & its Properties
*
……………………………………………………………………*
*
……………………………………………………………………*
pH Scale
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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

You CAN Pass Your Biology SOL!

Scientific Method

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 changeDEPENDENT VARIABLE (DV) The thing I measure Step 3: Setup a CONTROLLED EXPERIMENT. Each has:

  1. CONTROL GROUP: the group that stays the same (doesn’t receive the IV). It’s needed to compare.
  2. EXPERIMENTAL GROUP: the group that is manipulated (the group you are performing the experiment on). This group receives the IV. Step 4: Make a CONCLUSION or THEORY ⇒If the data gathered from your controlled experiment support your hypothesis, you accept your conclusion. ⇒If the data doesn’t support your hypothesis, start over!

How to Identify Variables on

a Graph:

*****Scientists use the SCIENTIFIC METHOD to help them answer questions and solve problems about the natural world.*****

Y

axis is the DV. The thing I measure X axis is the IV. The thing I change

Water makes life possible! It’s a universal solvent, comes in three states, and has a high specific heat to regulate temperature

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).

We do not want our body temperature

to fluctuate very much because it

would alter chemical reactions

( METABOLISM). When

metabolism is thrown off,

HOMEOSTASIS (balance) is also

Water & its Properties …………………………………………………………………… …………………………………………………………………… thrown off. This can lead to death!!!!

pH Scale

Macromolecules

*All living things are composed of 4 macromolecules. Macromolecules are large polymers (the prefix “poly” means “many”)

that are composed of lots of smaller building blocks called monomers (the prefix “mono” means “one”). *

  1. Carbohydrates: The only macromolecule that is used for ENERGY. Carbohydrate is a fancy word for SUGAR. The most important sugar is GLUCOSE ( C 6 H 12 O 6 ). The building blocks of carbohydrates are MONOSACCHARIDES.
  2. Lipids: The only macromolecule used to STORE ENERGY and to provide INSULATION. There are three classes of lipids (fats, oils & waxes). The building blocks of lipids are FATTY ACIDS.
  3. Proteins: The only macromolecule that can SPEED UP CHEMICAL REACTIONS and provide STRUCTURE & SUPPORT. The building blocks of proteins are AMINO ACIDS****.
  4. Nucleic Acids: The only macromolecules that TRANSMITS HEREDITY INFORMATION. There are two types of nucleic acids: DNA & RNA. Their building blocks are

NUCLEOTIDES.^ ……………………………………………………………………….………

Macromolecules

Enzyme

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.

  • The bigger the activation energy the slower the chemical reaction
  • The smaller the activation energy the faster the chemical reaction.

*Enzymes are biological catalysts. They speed up chemical reactions and regulate metabolism. Enzymes are proteins that can

lower a chemical reaction’s activation energy*

Enzymes

Transport

****Substances need to be able to travel into and out of cell across the cell membrane. This movement can either happen

spontaneously (by itself) or with the input of energy (ATP)****

There are two types of transport: PASSIVE & ACTIVE

  1. PASSIVE TRANSPORT: This moves substances across membranes from regions of high concentration to low concentration without energy.
  2. ACTIVE TRANSPORT: This moves substances across membranes from regions of low concentration to high concentration with energy (ATP)  Examples: Endocytosis & Exocytosis

There are 3 types of PASSIVE Transport:

  1. DIFFUSION: the movement of substances from a region of high concentration to low concentration.
  2. OSMOSIS: the movement of water from a region of high concentration to low concentration.
  3. FACILITATED DIFFISION: the movement of substances from high to low with the help of a transport protein. Metabolism

**** CELLULAR RESPIRATION and PHOTOSYNTHESIS are processes that allow cells to use and make energy to keep the cell

alive. They have a cyclical relationship with one another. They depend on one another!****

Cellular Respiration Photosynthesis

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 glucoseOUTPUTS (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.

CO 2 O 2

Glucose

Chloroplast

Mitochondria

DNA

**** DNA is a double‐helix composed of 2 complementary strands. It has 4 nucleotides composed of either A, T,C,or G: A pairs

with T, G pairs with C. This structure makes DNA REPLICATION and PROTEIN SYNTHESIS possible.!****

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.

Chromosome Structure:

DNA

(continued)

****The process of turning DNA into proteins follows a specific order. It starts in the nucleus and ends at the ribosome.****

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

****DNA is the cell’s genetic material. It must be copied before the cell can divide. To help with this, the DNA is packaging

into structures called CHROMOSOMES. Humans have 46 chromosomes that must be copied exactly before the cell can divide.

The process of cell division is called MITOSIS. Mitosis has 4 steps: PROPHASE, METAPHASE, ANAPHASE & TELOPHASE. ****

Genetics

**** GENETICS is the study of heredity. A GENE is a basic unit of heredity. An ALLELE is one of two or more alternative forms

of a specific gene. Two alleles make up a gene. GREGOR MENDEL crossed peas to develop the genetic theory we still use.****

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).