General Biology
Midterm Study Guide
Characteristics of Life (Chapter 1)
§ All living organisms must meet certain criteria in order to be considered living:
1. Organism must be made of cells
2. Organisms use energy (metabolism)
3. Organisms have features that help them to adapt to their surroundings
4. All organisms respond to their environment
5. Organisms grow
6. Organisms reproduce
7. Organisms maintain stable internal conditions (homeostasis)
Organic Compounds (Chapter 1)
§ Carbohydratesà used for quick energy; include sugars and starches
§ Lipidsà these are fats and are used to store energy
§ Proteinsà these help build and repair cells; building blocks of proteins are called amino acids.
§ Nucleic Acidsà DNA and RNA
Organism Needs (Chapter 1)
§ Organisms need: energy, air, water, proper temperature and a place to live
Life Processes (Chapter 1)
§ Ingestionà taking in food
§ Digestionà changing food to a usable form
§ Transportà movement of nutrients and waste products
§ Excretionà getting rid of waste products
Parts of the Microscope (Chapter 2)
§ The invention of the microscope allowed for huge advancements in science. Scientists use the microscope to study living things and this is why we know so much about different organisms, especially humans.
§ Total magnification= eyepiece (10x) X the objective lens (10 or 40 or 43)
Cells (Chapter 2)
§ Cells are the basic unit of life and carry out all life processes
§ First person to discover cells was Robert Hooke who looked at dead cork cells
§ Anton van Leeuwenhoek was the first person to observe living cells
§ Cell Theoryà all living things are made up of cells; cells are the basic unit of structure and function and carry out all life processes; cells come only from other living cells
§ The three main cell parts are :
Cell membraneà thin structure that surrounds and protects the cell
Nucleusà control center of the cell; controls all life processes; controls cell reproduction (contains the DNA)
Cytoplasmà gel-like interior of the cell where most of the cell’s activities take place
Cell Parts (Chapter 2)
§ Organelles are small structures suspended in the cytoplasm that perform a specialized job
§ Mitochondriaà store and release energy (ATP)
§ Endoplasmic Reticulumà system of tubes that move substances to different parts of the cell
§ Ribosomesà tiny structures that make proteins
§ Golgi Bodiesà package and distribute materials to other parts of the cell in vesicles
§ Vacuolesà small sacs used for storing food and waste. Plant cells have one large one for water storage
§ Lysosomesà “clean up crew” of the cell; rids the cell of waste
Cell Types (Chapter 2)
§ Prokaryoticà cells that have no nucleus or membrane bound organelles; examples include bacteria
§ Eukaryoticà cells that do have a nucleus and membrane bound organelles (“you” are made of eukaryotic cells)
§ Two types of eukaryotic cells include plant and animal cells
§ Animal Cellsà irregular shaped cells; these cells do not have cell walls, chloroplasts, or large vacuoles
§ Plant cellsà box-like cells; these cells do have cell walls, chloroplasts (for photosynthesis) and large vacuoles for water storage
Movement of Materials in and out of Cells (Chapter 2)
§ Diffusionà movement of a substance from an area of higher concentration to an area of lower concentration. Goal is equilibrium (equal on both sides of the cell)
§ Osmosisà diffusion of water molecules across a membrane
§ Active transportà requires energy to take place (think “activity”
§ Passive transportà does not require energy to take place
Energy for Cells (Chapter 2)
§ Cells perform many activities and all of them require energy, or the ability to do work or cause change
§ Animals are heterotrophs (organisms who must consume other organisms for energy)
§ Plants are autotrophs (organisms that make their own food)
§ Plants have to use the energy from the sun to make food. This is called photosynthesis. Byproducts include sugar and oxygen
§ Photosynthesis takes place in organelles called chloroplasts.
§ Plants and animals undergo a process known as cellular respiration which takes place in the mitochondria of the cell and releases energy from sugars for the cell to use to make ATP. Byproducts include carbon dioxide and water.
§ We give plants the carbon dioxide they need to perform photosynthesis and plants give us the oxygen we need for cellular respiration.
Climate Change
· Greenhouse Effect – Incoming sunlight energy heats Earth. Warmed Earth then radiates heat energy out. Greenhouse gases (water vapor, carbon dioxide, methane, etc.) trap some of this energy and prevent it from going into space.
· Burning fossil fuels like oil, gas and coal releases carbon dioxide, a greenhouse gas. Each year, humankind releases an increasing amount of carbon dioxide into the atmosphere. More carbon dioxide traps more heat, making the atmosphere warmer.
· In addition to increased carbon dioxide emissions per person, a major problem is that the human population is increasing very fast.
· Computer models of the climate predict that Earth’s temperature will increase somewhere in the range of 9 oF in the next 90 years (by 2100). One of the worst results of this global warming would be global sea level rise of 5 feet, flooding huge populated areas.