Unit One: Living Environment

Observation

What is seen or measured in an experiment.

Inference

A conclusion drawn based on observation or evidence.

Hypothesis

A prediction based on available evidence, typically stated as an 'if-then' statement.

Theory

An explanation of natural events supported by strong evidence, tying together many scientific facts, hypotheses, and laws.

Controlled Experiment

An experiment that compares results between two or more groups.

Experimental Group

The group in an experiment that receives the treatment being tested.

Control Group

The 'normal' group in an experiment that does not receive the treatment.

Placebo

A fake treatment given to the control group, often a sugar pill.

Independent Variable

The variable that is being tested in an experiment; plotted on the X axis.

Dependent Variable

The variable that is measured at the end of an experiment; the results, plotted on the Y axis.

Theory

An explanation of natural events supported by strong evidence, tying together many scientific facts, hypotheses, and laws.

Misconception about Theory

Theories are not mere opinions; they are scientifically supported explanations, not simple guesses.

Importance of Theories

Theories integrate and explain diverse scientific facts and concepts, providing a comprehensive understanding.

Nature of Scientific Theories

A scientific theory must be backed by evidence and can change over time with new information.

Controlled Experiment

An experiment that compares the results between two or more groups to understand the effect of a variable.

Experimental Design

Carefully planned experiments that ensure reliable comparisons between groups.

Factors in Controlled Experiments

Controlled experiments manipulate the independent variable while keeping all other conditions constant.

Examples of Theories

Examples include the Theory of Evolution and the Germ Theory of Disease, both backed by extensive evidence.

Hypothesis vs Theory

A hypothesis is a testable prediction, whereas a theory integrates and explains a body of evidence.

Role of Evidence in Theories

Strong evidence is crucial for establishing a theory, distinguishing it from mere conjecture.

Data Table

A structured format to organize data for plotting on a graph, featuring rows and columns.

Independent Variable

The variable that is manipulated or changed in an experiment, located in the first column of the data table.

Dependent Variable

The variable being measured in an experiment, found in the second column of the data table.

X-Axis

The axis on a graph where the independent variable is plotted.

Y-Axis

The axis on a graph where the dependent variable is plotted.

Most Common Elements in Living Things

The most common elements in living things, in order, are Carbon, Hydrogen, Oxygen, and Nitrogen (CHON).

Organic Compounds

Organic compounds contain both Carbon and Hydrogen (e.g., CHis is organic, H2O is not).

Size of Organic vs Inorganic Molecules

Organic molecules are larger than inorganic molecules.

Carbohydrates

Carbohydrates are sugars and starches made from simple sugars (like glucose) and supply energy.

Enzymes and Carbohydrates

Enzymes can break down starches and complex sugars into simple sugars.

Function of Lipids

Lipids store energy and include fats, oils, and waxes.

Proteins

Proteins are made from amino acids and are essential for building and running an organism's body.

Importance of Protein Shape

The shape of proteins determines their function and how they interact with other molecules.

Jobs of Proteins

Proteins serve various roles, including: 1) enzymes, 2) receptor molecules, 3) antibodies, and 4) hormones.

Enzymes

Enzymes are proteins that facilitate biochemical reactions in the body.

Enzymes

Enzymes are catalysts made from proteins that speed up chemical reactions.

Catalysts

Catalysts affect the rates (speed) of chemical reactions without being consumed.

Lock and Key Model

Enzymes fit only specific molecules; changing their shape renders them ineffective.

Effects of High Temperature on Enzymes

Very high temperatures can cause enzymes to lose their shape and cease functioning properly.

pH Scale

The pH scale measures acid and base strengths; low pH (0-6) is acidic, high pH (8-14) is basic, and 7 is neutral.

Homeostasis

Homeostasis is the balanced state in an organism necessary for survival.

Dynamic Equilibrium

Dynamic equilibrium refers to the body's ability to maintain balance by adjusting when disturbed.

Basic Life Functions

To maintain homeostasis, organisms perform functions like transport, nutrition, excretion, and respiration.

Metabolism

Metabolism encompasses all life processes necessary for living organisms.

Consequences of Homeostasis Failure

Failure to maintain homeostasis can result in disease or death.

Autotrophs

Organisms that make their own food through processes like photosynthesis.

Heterotrophs

Organisms that cannot make their own food and obtain nutrients by consuming other organisms.

Photosynthesis

The process by which autotrophs, primarily plants, algae, and blue-green bacteria, convert radiant energy from the sun into chemical energy in the form of sugar.

Chloroplasts

Organelles in plant cells where photosynthesis takes place, containing chlorophyll that captures sunlight.

Radiant Energy

The energy produced by the sun, which is essential for the process of photosynthesis.

Sugar Molecules

Products of photosynthesis, serve as energy sources for autotrophs and other organisms.

Role of Light in Photosynthesis

Light energy is captured by chlorophyll and is converted into chemical energy during photosynthesis.

Primary Producers

Organisms like plants and algae that can produce their own food and serve as a food source for heterotrophs.

Algae

A diverse group of autotrophic organisms that can photosynthesize, found mostly in aquatic environments.

Blue-Green Bacteria

Also known as cyanobacteria, these are autotrophs that perform photosynthesis and contribute to the oxygen supply on Earth.

What is Cellular Respiration?

Cellular respiration is the process that takes energy from sugar molecules and converts it into ATP, the energy source for all living things.

What are the main types of respiration?

The main types of respiration are aerobic respiration, which requires oxygen, and anaerobic respiration, which occurs without oxygen.

How does aerobic respiration differ from anaerobic respiration?

Aerobic respiration yields more ATP for a molecule of sugar compared to anaerobic respiration.

What is produced during anaerobic respiration in humans?

During anaerobic respiration, humans produce lactic acid, which can damage muscles and cause the sensation known as 'the burn' during exercise.

How are photosynthesis and aerobic respiration related?

Photosynthesis and aerobic respiration are opposite reactions, playing key roles in cycling oxygen, carbon, hydrogen, and water through the environment.

What is ATP?

ATP (adenosine triphosphate) is the energy currency of the cell, providing energy for various biological processes.

What is the main function of aerobic respiration?

The main function of aerobic respiration is to produce ATP using oxygen and sugar.

What happens to muscle cells during vigorous exercise?

During vigorous exercise, muscle cells may switch to anaerobic respiration, leading to the accumulation of lactic acid.

What role do enzymes play in cellular respiration?

Enzymes facilitate the biochemical reactions involved in cellular respiration, increasing the efficiency of ATP production.

Why is oxygen essential for aerobic respiration?

Oxygen is essential for aerobic respiration as it acts as the final electron acceptor in the electron transport chain, allowing for maximum ATP production.

What is the cell theory?

The cell theory states that: 1) All living things are made of one or more cells. 2) Cells carry out all life functions. 3) All cells come from other cells.

What is the function of the cell membrane?

The cell membrane controls movement into and out of the cell and is made of lipids and proteins.

What is the role of the nucleus?

The nucleus houses the cell's genetic material and controls cell activities.

What do chloroplasts do?

Chloroplasts are organelles in plant cells that perform photosynthesis, converting sunlight into energy.

What is the function of mitochondria?

Mitochondria are the powerhouse of the cell, generating ATP through cellular respiration.

What is the cytoplasm?

Cytoplasm is the gel-like substance within the cell membrane that holds organelles and facilitates cellular processes.

What do ribosomes do?

Ribosomes are responsible for protein synthesis in the cell.

What is the function of vacuoles?

Vacuoles are storage organelles; plant cells have large vacuoles for storing nutrients and waste, while animal cells have smaller vacuoles.

What is the cell wall?

The cell wall provides protection and support for plant cells; it is not found in animal cells.

What are the differences between plant and animal cells?

Plant cells have cell walls and chloroplasts, while animal cells do not. Animal cells have centrioles and smaller vacuoles compared to the larger vacuoles in plant cells.

What is the chromosome count in humans?

Humans have 46 chromosomes, which are organized into 23 homologous pairs.

Common misconception about chromosome numbers?

A common mistake is to say that humans have 23 chromosomes, 46 pairs, or other incorrect counts.

What do chromosomes contain?

Each chromosome has hundreds or thousands of genes.

What is the function of genes?

Each gene codes for a particular protein.

Common misconception about genes and proteins?

A common mistake is to say that genes/DNA are made from protein; genes are made from nucleic acids.

What are the building blocks of DNA?

DNA is made of four bases: A, T, C, and G.

What does a three-letter codon represent?

A three-letter codon represents a specific amino acid.

What are the base pairs in DNA?

Base pairs are A-T and C-G; in RNA, they are A-U and C-G.

What is the role of RNA?

RNA carries the genetic code to ribosomes, where proteins are synthesized.

What are mutations?

Changes to DNA are called mutations, and they can only be passed on if they occur in reproductive cells.