7th Grade - Science - Chapter 1

cell

basic unit of structure and function in living things

microscope

an instrument that makes small things look larger

cell theory

a widely accepted explanation of the relationship between cells and living things

cell wall

a rigid layer that surrounds the cells of plants and some other organisms

cell membrane

controls which substances pass into and out of a cell

nucleus

a large oval structure that acts as a cell's control center, directing all of the cell's activities

organelles

a tiny cell structure that carries out a specific function within the cell

ribosomes

small grain-shaped organelles that produce proteins

cytoplasm

the thick fluid region of a cell located inside the cell membrane or between the cell membrane and nucleus

mitochondria

an organelle that converts energy stored in food to energy the cell can use to live and function

endoplasmic reticulum

an organelle with a network of membranes that produce many substances

golgi apparatus

an organelle that receives proteins and other newly formed materials from the ER, packages them, and distributes them to other parts of cell or to the outsides of the cell

vacoule

a organelle that stores water, food, or other materials needed by the cell

chloroplast

an organelle that captures energy from sunlight and changes it to a form of energy cells can use in making food

lysosomes

an organelle that contains large substances that break down large food particles into smaller ones

multicellular

multi-celled organisms

unicellular

single-celled organisms

tissue

a group of similar cells that perform the same function.

organ

made of different kinds of tissues that function together

organ system

a group of organs that work together to perform a major function.

elements

any substance that cannot be broken down into simpler substances

compounds

form when two or more elements combine chemically

carbohydrates

energy-rich organic compounds made of the elements carbon, hydrogen, and oxygen

lipids

compounds that are made mostly of carbon and hydrogen and some oxygen

proteins

large organic molecules made of carbon, hydrogen, oxygen, nitrogen, and, in some cases, sulfur

enzymes

a group of proteins that speed up chemical reactions in living things

nucleic acids

very long organic molecules

DNA

the genetic material that carries information about an organism and is passed from parent to offspring

double helix

the shape of a DNA molecule

selectivly permeable

some substances can pass through the membrane while others cannot

passive transport

the movement of substances across a cell membrane without the use of energy by the cell

diffusion

the process by which molecules move from an area of higher concentration to an area of lower concentration

osmosis

the diffusion of water through a selectively permeable membrane

active transport

the movement of materials across a cell membrane using cellular energy

endocytosis

when the cell membrane changes shape and engulfs the particle

exocytosis

process by which a cell releases large amounts of material

all living things are composed of cells / cells are the basic units of structure and function in living things / all cells are produced from other cells

What does the cell theory state?

some microscopes focus light through lenses to produce a magnified image, and other microscopes use beams of electrons

How do microscopes work?

a different function

Each kind of cell structure has what within a cell?

tissues / organs / organ systems

How are cells organized in multicellular organisms?

carbohydrates / lipids / proteins / nucleic acids / water

What compounds do cells need?

passive transport / active transport

What are the 2 processes in which substances can move into an out of a cell?

the way its cells are put together

What does the structure of a living thing depend on?

live / grow / reproduce

An organism’s functions are the processes that enable it to do what?

obtaining oxygen, food, and water / getting rid of wastes

What are the functions of a cell?

absorb food which provides your body with energy and materials needed for growth

What do cells in your digestive system do?

get oxygen

What do cells in your lungs do?

keep you alive

What do your cells working together do?

it must carry out many of the same functions as the entire organism

What must a cell do to stay alive?

1590

When was the first microscope made?

built his own microscopes in the drawings of what he saw / looked at dead bark / came up with the term cell / never knew the importance of what he saw

What did Robert Hooke do?

first to see a living cell through a microscope

What did Anton van Leeuwenhoek do?

concluded that all plants are made of cells

What did Matthias Schleidan do?

concluded that all animals are made of cells

What did Theodor Schwann do?

figured out that all cells come from cells

What did Rudolf Virchow do?

the functions that living things perform

Cell can provide clues about what?

growth and reproduction

Because all cells come from cells, scientists can study what?

magnification / resolution

What 2 properties must a microscope have to be useful?

magnification

the condition of things appearing larger than they are

convex lens

a lens that has a center that is thicker then its edge

the image is magnified

What happens when light passes through a convex lens and into your eye?

how you see objects / reveals details that you may not have known were there

What does magnification change?

compound microscope

What type of microscope has two lenses?

eyepiece / from a revolving nose piece

Where are the lenses in a compound microscope?

magnify an object more

What can a compound microscope do that a single lens can't?

light passes through the object on the slide, the lower lens, and then the lens in the eyepiece

How does a compound microscope work?

200x

If a compound microscope has one lens that magnifies an object 10 times, and the other lens magnifies the object 20 times, what is the total magnification?

use a metric ruler to measure the size of the circular field in millimeters as you can see it through the microscope, bar then you can estimate the size of the object you see by comparing it to the width of the field

How do you measure microscopic objects?

resolution

the degree to which two separate structures that are close together can be distinguished

more

Better resolution shows more or less details?

individual dots

ex. the colors of a newspaper photograph may appear to your eye to be solved patches of color, however, if you look at the colors through a microscope you will see what?

resolution increases

Usually what happens as magnification increases?

they use a beam of electrons instead of light to produce a magnifying image

How do electron microscopes work?

pictures that are too small to be seen with white microscopes

By using a electron microscope, scientist can obtain light?

higher magnification and better resolution than light microscopes

What do electron microscopes allow?

no

Do animal cells have cell walls?

helps protect and support the cell

What does a plant’s cell wall do?

cellulose

What are cell walls made of?

water and oxygen

What can still pass with the cell wall easily?

through the cell membrane

How does everything a cell need, such as food particles, water, oxygen enter?

through the cell membrane

How do wastes leave the cell?

both plant and animal cells

Do plant and/or animal cells have a cell membrane?

nuclear envelope

What is the nucleus surrounded by?

nuclear envelope

Materials pass in and out of the nucleus through pores in what?

chromatin

thin strands of material that fill in the nucleus and contain information for directing a cells function

cytoplasm

What moves constantly inside of cell?

cytoplasm

What organelle carries along the nucleus and other organelles that have specific jobs?

mitochondria

What organelles called the “powerhouse” of a cell?

the Endoplasmic Reticulum

Ribosomes dot some parts of what, while other ribosomes float in the cytoplasm?

helps attached ribosomes make proteins

What does the ER do?

cell wall / endoplasmic reticulum / chloroplasts / mitochondria / vacuole / golgi apparatus / cytoplasm / cell membrane / ribosomes / nucleus

What organelles are in a plant cell?

cell membrane / golgi apparatus / lysosomes / mitochondria / ribosomes / vacuole / cytoplasm / endoplasmic reticulum / nucleus

What organelles are in a animal cell?

the golgi apparatus

Where do proteins go after they leave the endoplasmic reticulum?

flattened sacs and tubes

What does the golgi apparatus look like?

water / food / other materials needed by the cell / waste products until they're removed

What do vacuoles store?

because the leaf contains many chloroplasts

Why do chloroplasts make leaves green?

old cell parts and release the substances so they can be used again

What do lysosomes also break down?

as a recycling center

How can we think of lysosomes?

key functions

All cells in a multicellular organism must carry out what?

getting oxygen

What is an examples of key functions?