Chapter One Flashcards
What is nature?
everything in the world except what humans have created.
List the levels of life’s organization
Atom, molecule, cell, tissue, organ, organ system, multicelled organism, population, community, ecosystem, biosphere
Describe atom
fundamental units of all substance
Describe molecule
2 or more atoms joined in a chemical bond. Only living cells make the molecules of life
Describe cell
smallest unit that can live and reproduce on its own or as a part of a multicelled organism
Describe tissue
organized array of cells and substances that are interacting in some task
Describe organ
structural unit of two or more tissues that interact in one or more tasks
Describe organ system
organs that interact in one more tasks
Describe multicelled organisms
individual made of different types of cells
Describe population
group of single celled or multicelled individuals of a species in a given area
Describe community
all populations of all species in a specified area
Describe ecosystem
a community that is interacting with its physical environment through inputs and outputs of energy and materials
Describe biosphere
Most inclusive level - all regions of Earth’s waters, crust, and atmosphere that hold organisms
Define emergent properties
characteristics of a system that do not appear in any of its component partsex: cells have life, but its component parts (molecule and atom) do not have life, thus life is an emergent property of a cell
Define energy
The capacity to do work
Define nutrient
A particular type of atom or molecule that has an essential role in growth and survival
Define producers
One of two broad categories, get energy and simple raw materials from environmental sources and make their own foodex: plants use energy from the sun to make sugars from CO2 and water and the sugars function as packets of immediately available energy or as building blocks for larger molecules
Define consumers
One of two categories, cannot make their own food and get their energy and nutrients indirectly - that is, from eating producers and other organismsex: animals and decomposers (feed on wastes and remains of organisms)
True or False? Energy and nutrients are cycled among producers and consumers.
False. Nutrients is cycled among the producers and the consumers, but energy flows one way (from the environment to producers to consumers) With each transfer, heat is lost (mainly through metabolic heat)
Define receptor
a molecule or cellular structure that responds to a specific form of stimulation, such as the energy of sunlight or the mechanical energy of a bite.
What happens when a receptor is stimulated?
trigger changes in activities of organisms ex: after eating, body responds to input of sugars by producing insulin and stuff
Define homeostasis
the way organisms sense and adjust to change to keep conditions of their internal environment (blood and tissue fluids) within range that favours cell survival
Why is DNA important?
It is the basis of growth, survival, and reproduction, and is the source of each organism;s distinct features or traits
What does DNA contain?
instructions. Cells use the instructions to make proteins (long chains of amino acids)