Science 8 Final Exam Vocabulary

Words and definitions that will help you study for your 8th grade Science Final Exam

observations

scientific data taken from the 5 senses

inferences

conclusions drawn from observations and prior knowledge.

hypothesis

a testable prediction about the outcome of an experiment that follows a “if…then…because” format

independent variable

the variable that is changed or controlled in a scientific experiment to test its effects on the dependent variable.

dependent variable

the variable that you can NOT control in an experiment, which is measured and affected by changes in the independent variable

control

the test group that has nothing done to it or is kept constant for comparison

variable

a factor that can change in an experiment

eyepiece

the part of a microscope that contains the lens you look through, typically providing an enlarged view of the specimen

base

the bottom part of a microscope that supports the entire structure and keeps it stable during use and while carrying it

objectives

lenses on a microscope that provide varying levels of magnification (4x, 10x, 40x)

arm

the part of a microscope that connects the base to the eyepiece and supports the optical components, providing a handle for carrying the microscope

stage

the platform of a microscope where specimens are placed for viewing, often equipped with clips to hold slides in place

stage clips

the small devices on a microscope's stage that hold the slides in place to prevent movement during observation

coarse adjustment

a knob on a microscope used for initially focusing on a specimen by changing the distance between the objective lens and the slide NEVER USED on the 40x zoom to avoid damaging the slide or lens

fine adjustment

a knob on a microscope used for precise focusing on a specimen, allowing for clearer detail, typically used after coarse adjustment

Diaphragm

a device on a microscope that controls the amount of light reaching the slide, enhancing contrast and visibility of the specimen

diffusion

the process by which molecules NATURALLY spread from areas of high concentration to areas of low concentration, resulting in uniform distribution

osmosis

diffusion of water

active transport

this is moving particles from a low concentration to high concentration and REQUIRES ENERGY

passive transport

the movement of molecules across a cell membrane without the use of energy, typically from high to low concentration.

ATP

is the primary energy source of the cell, providing energy for various cellular processes

endocytosis

is the process by which cells take in outside substances, bringing them into the cell in a vesicle-requires energy

exocytosis

is the process by which cells get rid of substances, releasing them outside of the cell in a vesicle; it requires energy

cell

the basic structural and functional unit of all living organisms.

prokaryotic

cells that lack a nucleus and membrane-bound organelles, typically unicellular

eukaryotic

cells that have a nucleus and membrane-bound organelles, often multicellular

nucleus

the control center of the cell that contains genetic material

DNA

a molecule that carries the genetic instructions used in growth, development, functioning, and reproduction of all known living organisms

unicellular

organisms that consist of a single cell

multicellular

organisms that consist of multiple cells, often with specialized functions

differentiation

the process by which cells become specialized in structure and function

stem cells

undifferentiated cells that can divide to produce various cell types (blank cells)

organelle

specialized structures within a cell that perform specific functions, such as mitochondria and ribosomes

cell wall

a rigid outer layer that surrounds the cell membrane in plant cells, providing support and protection

cell membrane

the semipermeable membrane surrounding the cytoplasm of a cell, regulating the movement of substances in and out

ribosome

makes proteins; found on the endoplasmic reticulum or in cytoplasm

mitochondria

the powerhouse of the cell, where energy (ATP) is produced through cellular respiration

vacuole

a membrane-bound organelle that stores nutrients, waste products, or other materials in a cell

lysosome

a membrane-bound organelle that contains digestive enzymes to break down waste and cellular debris

endoplasmic reticulum (ER)

a network of membranes within a cell that assists in the production, processing, and transport of proteins

chloroplast

a membrane-bound organelle in PLANT cells that is responsible for photosynthesis, converting sunlight into energy

cytoplasm

the gel-like substance within a cell that contains organelles

photosynthesis

the process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll

cellular respiration

the process in which cells convert glucose and oxygen into energy, producing carbon dioxide and water as byproducts

respiration

the biochemical process in which cells convert nutrients into energy, typically involving oxygen and releasing carbon dioxide as a waste product (ex. humans breathing)

lungs

paired organs in the respiratory system responsible for gas exchange, allowing oxygen to enter the blood and carbon dioxide to be expelled

heart

a muscular organ that pumps blood throughout the body, supplying oxygen and nutrients while removing waste products

artery

a blood vessel that carries oxygenated blood AWAY from the heart to the tissues of the body

vein

a blood vessel that carries deoxygenated blood BACK to the heart from the tissues of the body

capillaries

tiny blood vessels that connect arteries and veins, allowing for the exchange of oxygen, nutrients, and waste between blood and tissues

stomach

an organ that breaks down food using acids and enzymes, playing a key role in digestion

large intestines

the final part of the digestive system, responsible for absorbing water and electrolytes from indigestible food matter and forming waste for elimination

small intestine

the part of the digestive system where most of the digestion and nutrient absorption occurs, following the stomach and preceding the large intestines

esophagus

a muscular tube that connects the throat to the stomach, allowing for the passage of food

diaphragm

a dome-shaped muscle that separates the thoracic cavity from the abdominal cavity and plays a crucial role in the breathing process by contracting and relaxing

stomach

the organ where food is mixed with digestive juices and broken down into a semi-liquid form before entering the small intestine

pancreas

a gland that produces digestive enzymes and hormones, including insulin, playing a key role in regulating blood sugar levels and aiding digestion

liver

a vital organ that processes nutrients from the digestive tract, detoxifies harmful substances, and produces bile to aid in digestion

nerve cell

a specialized cell that transmits electrical impulses, facilitating communication between different parts of the body and playing a crucial role in the nervous system

biodiversity

the variety of life in the world, including species diversity, ecosystem diversity, and genetic diversity, essential for ecosystem to sustain life and maintain ecological balance

biome

a large geographical area, characterized by its climate, soil, plants, and animals, such as forests, deserts, and grasslands

population

a group of individuals of the same species living in a specific area, interacting with each other and sharing resources

community

a group of different species living together in a specific area, interacting with one another and forming relationships that contribute to the ecosystem

ecosystem

a biological community of interacting organisms and their physical environment, functioning together as a system

organism

any living thing that can act independently, including animals, plants, fungi, and microorganisms

abiotic factors

the non-living components of an ecosystem

biotic factors

the living components of an ecosystem

primary ecological succession

the process of change in the species structure of an ecological community over time, beginning in a lifeless area

secondary ecological succession

the process of change in species composition that occurs in an area where a disturbance has destroyed an existing community but left the soil intact

pioneer organisms

the first species to colonize previously disrupted or damaged ecosystems, leading to ecological succession

habitat

the natural environment in which a species lives, providing food, shelter, and mates for reproduction

herbivore

an animal that primarily consumes plants as a food source

carnivore

an animal that primarily consumes other animals as a food source

omnivore

an animal that consumes both plants and animals as food sources

primary consumer

an organism that feeds on primary producers, such as plants, in a food chain

secondary consumer

an organism that feeds on primary consumers, such as herbivores, in a food chain

decomposers

organisms that break down dead organic material and return nutrients to the soil

niche

the role or function of an organism within its ecosystem, including its habitat, resource use, and interactions with other organisms

climax community

a stable and mature ecological community that undergoes little change in species composition

introduced species

a non-native species that is brought to an ecosystem by human activities, potentially causing harm to native species and ecosystems

native species

a species that naturally occurs and evolves in a specific ecosystem without human intervention

invasive species

a non-native species that spreads rapidly in a new environment, disrupting local ecosystems and outcompeting native species

pollution

the introduction of harmful substances or contaminants into the environment, impacting air, water, and soil quality

wetlands

ecosystems characterized by very wet soils and standing water, supporting diverse plant and animal life

genetics

the study of heredity and variation in organisms, focusing on how traits are passed from parents to offspring

genes

the basic units of heredity found in DNA, responsible for building and maintaining an organism's traits and characteristics

genotype

the genetic constitution of an organism, representing the combination of alleles inherited from its parents

phenotype

the observable physical or biochemical characteristics of an organism, determined by its genotype and environment

alleles

different versions of a gene that can exist at a specific spot on a chromosome, influencing the traits of an organism

dominant traits

traits that are expressed phenotypically when at least one dominant allele is present in the genotype

recessive traits

traits that are expressed phenotypically only when two non-dominant alleles are present in the genotype

homozygous

having two identical (SAME) alleles for a particular gene, either dominant or recessive

heterozygous

having two different alleles for a particular gene, one dominant and one recessive

Punnett Square

a diagram used to predict the genotype and phenotype ratios of offspring from a genetic cross

codominance

a genetic scenario where both alleles in a heterozygous genotype express themselves fully and separately

nucleotides

the building blocks of DNA and RNA, composed of a sugar, phosphate group, and nitrogenous base

double helix

the structure of DNA consisting of two intertwined strands that resemble a twisted ladder

deoxyribose sugar

the sugar component of DNA nucleotides, which contains one less oxygen atom than ribose sugar found in RNA

adenine

a nitrogenous base that PAIRS WITH THYMINE in DNA and uracil in RNA, playing a key role in the encoding of genetic information

guanine

a nitrogenous base that PAIRS WITH CYTOSINE in DNA and RNA, contributing to the structure and function of nucleic acids