CRT Study Guide

• A well-known scientist who built the most powerful microscope of his time was __________________________.

• His invention was considered a major contribution to science.

answer

van Leeuwenhoek

question

• Bacteria, which is made of ____________ ___________, are known to be the simplest organisms.

answer

single cells

question

• Most cells have a ___________. This cell structure is sometimes called the “brain” of the cell because its function (job) is to “control all of the cell’s activities.” It controls how and when the cell grows, develops, and divides.

answer

nucleus

question

• The __________ ____________ is a cell structure that is common to both plant and animal cells. Its function (job) in both is to “control the movement of substances into and out of the cell.”

answer

cell membrane

question

• _____________________ is a jelly-like substance found in plant and animal cells. It fills most of the cell and has other cell structures floating in it. It is made up mostly of water.

answer

cytoplasm

question

• When an organism is made up of many cells and different kinds of cells, each kind of cell has a special______________________. For example, blood cells have a different job than muscle cells. They each have a different job to do, and that keeps us alive and healthy.

answer

function

question

• There are two cell structures that are found ONLY in plant cells. They are ______ ________ and the ___________________. You will never find these cell structures in animal cells!

answer

cell wall and

chloroplasts

question

• When sunlight passes through a prism, the light _______________________________________ called the visible spectrum.

answer

separates into different colors

question

•When light colors are ______________, we CANNOT see the color.

answer

absorbed

question

•The “bending of light as it moves from one material to another” is known as ______.

answer

refraction

question

• Farsighted means a person CAN see far away (distant) objects clearly, but close (nearby) objects look blurry. Glasses with ____________ lenses correct farsighted vision.

answer

convex

question

• The part of the eye that light passes through to help us see nearby objects is called the ____________.

answer

• lens

question

• On a rainy day, you may observe a ______________ in the sky as light passes through raindrops. This is because raindrops are like tiny prisms in the air.

answer

rainbow

question

• If you see an object such as a green car, you know that the color green is the color that is reflected…not absorbed. You will not see the colors that are absorbed. Therefore, when you look at grass, you know that __________ is not absorbed.

answer

green

question

• The function of the _____________ in the human eye is to “control the amount of light that enters the pupil.”

answer

iris

question

• We know that a ___________ reflects the most light of common household objects. That is why you can see your own image, as well as other images of differing colors, in one.

answer

mirror

question

•The _________ is the part of the eye that bends light rays.

answer

cornea

question

•The “bouncing back of light from a surface” is known as ________________.

answer

reflection

question

• When you see your image in a mirror, ________________ are bouncing back from the surface of the mirror. This is what allows you to see your reflection.

answer

light rays

question

• A person who can see nearby objects clearly but cannot see distant objects is nearsighted. A nearsighted person’s vision would be corrected by wearing glasses that have ____________ lenses.

answer

concave

question

• Tilting a mirror in front of your face so that you are changing the angle of the light ray hitting the mirror, prevents you from seeing your own face but instead ___________________.

answer

another image

question

• Contact lenses are a type of corrective lens for people who “need glasses”. They work to correct vision because they are very similar to the ___________ in the human eye.

answer

• cornea

question

• The reason you SEE colors of objects is that the object is reflecting the light color that you are seeing. It absorbs all the other light colors of the visible spectrum. So, when you notice that an apple is red, you know that it is _____________________________.

answer

reflecting light