bio test #1

what is biology?

the study of life

what is science? science has limits and values evidence/data.

a body of knowledge (data) about the natural world

what drives science?

inquiry/curiosity

what are the steps of the scientific method?

1. observation
2. hypothesis
3. prediction
4. experiment
5. analyze data
6. accept/reject hypothesis
7. communicate (repeat)

step 1 of scientific method: observation

- question/problem
- what gets you started
- must be reproducible
- observation + description, measurement, or record of any object/phenomenon

step 2 of scientific method: hypothesis + requirements

- bold statement --\> NOT a question (educated guess)
- 2 requirements: testable and falsifiable/refutable
- informed, logical, and plausible explanation for observations of the natural world
- can NEVER be proven, only support it

step 3 of scientific method: prediction

- tells what to expect if hypothesis is supported
- "if...then..." statement
- if \= independent variable
- then \= dependent variable
- doesn't mean you're gonna get it, just a prediction of what will happen

step 4 of scientific method: experiment

- repeatable manipulation of one or more aspects of the natural world
- must be very detailed, comprehensive, consistent, and reduce bias

variable

anything that can change (in an experiment)

independent variable

that which the scientist manipulates (I change)

dependent variable

any variable that responds or could potentially respond to changes in the independent variable (what's being measured)

control

baseline for comparison that doesn't change during the experiment and doesn't affect the dependent variable

constants

factors that stay the same throughout the entire experiment (ex: amount of food, water, etc.)

correlation

two or more aspects of the natural world behave in an interrelated manner

is this example a causation or correlation? ex: the precent of high schoolers graduating and moving onto college and an increase in global average temperatures

correlation

causation

one variable causes the change in the second variable

is this example a causation or correlation? ex: as population increases the more high school graduate move onto college

causation

what is a scientific claim?

- statement that's made about the natural world that can be tested using the scientific method
- anyone can make one
- many of them aren't true

what is scientific literacy and why is it important?

- it's an understanding of the basics of science and the scientific process
- it's important because it enables us to make informed decisions about the world around us; it also enables us to communicate our knowledge to others

4 major things to consider when evaluating scientific claims

1. real vs pseudo science
2. bias/agenda
3. peer review/publication
4. credentials

real vs pseudo science

- real: follows scientific method
- pseudo: characterized by scientific-sounding statements, beliefs, or practices that aren't based on the scientific method

bias/agenda

- bias: a prejudice or opinion for or against something
- this is bad/very dangerous

applied research

- businesses and industries provide the majority of funding to find practical uses for scientific discoveries
- money is a strong factor/motivator to support or reject a claim

basic research

- intended to expand fundamental knowledge of science
- largely funded by federal government

types of literature

1. primary
2. secondary
3. social media

primary literature

- first publication of scientific research that contains actual data with controls (includes peer review)
- ex: technical reports, conference proceedings, dissertations, peer-reviewed science journals

secondary literature

- summary of primary literature; sources that give a basic overview of topic or summarizes research results (must cite original study and have credible credentials)
- ex: our textbook, review articles, popular scientific journals, respected institutions on the internet (like National Geographic)

social media

- literally anything else
- NOT a good source
- ex: twitter, instagram reels, TikTok, Facebook posts, etc.

everything is made up of \__________ (anything that has mass and takes up space)

matter

each piece of unique matter we can an \_________ - a pure substance that has distinct properties and cannot be broken down

element

the smallest amount of an element (in pure form) is called an

atom

together atoms make

molecules

what element is found in living organisms that is rare in non-living things?

carbon

isotope practice problem: nitrogen-11 is an isotope of nitrogen that has 7 protons and 4 neutrons. what is the atomic number and atomic mass number (atomic weight) of nitrogen-11?

- atomic number: 7
- atomic mass number: 11

what is an isotope?

forms of atoms that have the same number of protons, but differing number of neutrons; difference \# of neutrons means differing weight and unstable nucleus

covalent bonding

sharing one or more electrons to form molecules

ionic bonding

giving or receiving electrons

hydrogen bonding

- WEAK covalent bond
- uneven distribution of charge that allows water to form weak bonds
- almost every chemical reaction that occurs in living organisms is associated with water
- water has special properties such as being a polar molecule

hydrophobic

- water-fearing
- substance doesn't dissolve in water
- non polar molecules

hydrophilic

- water loving
- substance dissolves in water
- polar molecules

biomolecules

- big molecules that pertain to life
- contain at least carbon-hydrogen bond

what are the 4 major biomolecules?

1. carbohydrates
2. proteins
3. lipids
4. nucleic acids

carbohydrates

- composed of monosaccharides (single sugars) held together by covalent bonds
- function: short-term energy storage and immediate-term energy

proteins

- polypeptide chains that are folded into 3D shapes
- composed of amino acids that are held together by peptide bonds
- order of amino acids matter because it determines the protein that's made and its specific function
- if protein loses its shape, it loses its function \= this is when it's denatured
- functions: storage, cell transport, structure, catalysis

lipids

- made up of macromolecules?
- function: long-term energy storage

nucleic acids

- made up of nucleotides
- 2 types: DNA and RNA

what is pH?

the measure of the concentration of hydrogen ions

pH scale

- ranges from 0-14
- lower the number, the more H+ ions in a solution
- 0-6 are acids; acids donate H+ ions into solutions
- 7 is neutral
- 8-14 are bases; bases accept H+ ions
- it's 10x the number on the scale (so pH of 3 is 10x more acidic than a pH of 4 and a pH of 3 is 100x more acidic than a pH of 5)

6 requirements of living organisms

1. every organism is composed of one or more cells.
2. living organism can autonomously reproduce. composed of DNA (genetic material that contains all of the instructions to build, maintain, and GROW)
3. living organisms must obtain energy from their environment
4. living organisms sense their environment and respond to it (respond to stimuli)
5. living organisms maintain internal conditions; homeostasis
6. groups of living organisms can evolve

what is the smallest unit of life?

cell

why are cells so small?

- a large surface area to volume ratio is important
- more surface area you have \= more space for nutrients to go in and waste to go out

cell theory (2 parts)

1. every living organism is composed of one or more cells
2. all cells living today came from preexisting cells

prokaryotes

- NO nucleus
- single celled
- bacteria and archaea (bacteria do have ribosomes)
- on average, much smaller than eukaryotic cells
- most have a tough cell wall
- lack membrane bound organelles (ribosomes present in cytoplasm)
- usually have cilia, flagellum, or both

eukaryotes

- ALL of these have a nucleus
- internal complex compartments (membrane bound organelles)
- can be BOTH single celled or multicellular

what does eukarya mean?

"true nucleus"

active transport

- movement of substances across a membrane requiring energy (ATP)
- energy IS required

passive transport

- movement of substances across a membrane without addition of energy
- NO energy is required

cytoplasm

- contains a thick fluid called cytosol, consisting of ions and biomolecules mixed in water
- cytosol + organelles \= cytoplasm
- would be air of the city

nucleus

- contains DNA
- think of it like the courthouse/city hall building, important documents are kept there

nucleolus

- site of RNA used later by the cell
- it's the copy machine (RNA is a copy of DNA since DNA can't leave nucleus)

endoplasmic reticulum (er)

- interconnected network of tubes and flattened sacs that produces certain lipids and proteins

rough er

- dotted with ribosomes that produce proteins for use both inside and outside the cell
- factory where proteins are made

smooth er

- produce lipids for other cellular compartments and help break down toxic organic compounds in the cell
- think of it as the factory that synthesizes lipids and carbs

Golgi apparatus

- directs proteins and lipids produced by ER to their final destination
- packages and ships proteins, carbs, lipids to where they need to go
- it's like the post office

mitochondria

- extracts energy from food molecules, releasing carbon dioxide and water in an oxygen-dependent process called cellular respiration
- ATP powerhouse
- it's the power station

cytoskeleton

- framework and structure/skeleton of buildings

lysosomes

- only in animals
- breaks down organic molecules when you're done with them
- it's the trash can

flagella

- only in animals
- aids in swimming/movement
- sperm

central vacuole

- only in plants
- holds water
- water tower
- chloroplasts

cell wall

- to give structure and support
- only in plants

chloroplasts

- only in plants
- capture energy from sunlight to make sugars (glucose)
- does photosynthesis

what organelles are only found in plants?

cell wall, chloroplasts, central vacuole

what organelles are only found in animals?

flagella, lysosomes

energy

the transfer of electrons and is important for life

first law of thermodynamics

energy can neither be created nor destroyed, but can be converted from one form to another

what is metabolism?

- the chemical reactions occurring inside a living organism
- ability to capture, store, and use energy

two types of metabolism

1. catabolism
2. anabolism

catabolism

energy producing reactions that release chemical energy in the process of breaking down complex biomolecules
- breaking bonds, releasing energy

anabolism

energy requiring reactions that create complex biomolecules from smaller organic compounds
- building bonds, investing/creating energy

what is the most abundant energy carrying molecule?

ATP

enzymes are what organic molecule?

proteins

enzymes are catalysts. what does that mean?

they speed up chemical reactions

how do enzymes speed up reactions?

by lowering the amount of energy necessary for the reaction to run - producing more product

enzymes are substate specific. (specificity). what does that mean?

each enzyme matches a specific reaction; these are certain shapes that the 3D enzymes fit in to

enzymes are 3D shapes. the location that the substrate binds to the enzyme is called the?

active site

enzymes are reusable unless

denatured

denaturation

the destruction of a protein's shape, resulting in a loss of protein activity

when an enzyme loses its function it is said to be denatured. what are 3 things that change an enzyme's shape?

1. extreme temps
2. pH outside of optimal range
3. change in salt concentration (salinity)

what is a metabolic pathway?

- chains of linked chemical reactions
- produce key biological molecules in a cell
- break down key biological molecules in a cell
- 2 important types: photosynthesis and cellular respiration

what is photosynthesis?

taking light energy and turning it into chemical energy (glucose)

where does photosynthesis take place?

chloroplast

who does photosynthesis?

plants and some bacteria

2 stages of photosynthesis

1. light reaction
2. Calvin cycle

light reaction

- needs light and water
- light splits water molecule into H+ and O which generate energy carries NADPH and ATP
- oxygen isn't needed so it's released through a pore in the leaf called the stomata
- whole purpose of light reaction is to run dark reaction/Calvin cycle

Calvin cycle

- energy from light reaction is used to run a series of enzyme catalyzed chemical reactions to convert carbon dioxide into sugar
- does not require light
- whole purpose is to convert carbon dioxide into sugar (glucose)

What are the reactants of photosynthesis?

carbon dioxide and water

What are the products of photosynthesis?

glucose and oxygen

what is cellular respiration?

- the breakdown of food molecules to release a form of energy that's usable within a cell

Who does cellular respiration?

all living things

What are the reactants of cellular respiration?

glucose and oxygen