Download Intro to Cells

Cells
 All living life forms are made of cells
 All cells have the same basic structure
Discovery of Cells
 Robert Hooke is known for using the microscope to
look at pieces of a cork
 Those pieces reminded him of little boxes or what he
called “cells”
 Anton van Leeuwenhoek used a more powerful
microscope to discover tiny animals in pond water
 He called them animacules
 We know now he saw single celled organisms
Cell Theory
 All living things are made up of one or more cells
 Cells are the basic units of structure and function in
organisms
 All cells arise from existing cells
1.
Which of the following led to the
discovery of cells?
A. Electricity
B. Computers
C. Microscopes
D. Calculators
2.
Which of the following is part of
the cell theory?
A. All living things are made of one cell
B. Cells are the basic units of structure and function in
organisms
C. Most cells arise from existing cells.
D. Cells are nonliving units that make up organisms
Looking at Cells
 A cell’s shape reflects the cell’s function
 Cell Shapes:
 Branched
 Flat
 Round
 Rectangular
 There are at least 200 types of cells
 The human body is made up of 100 trillion cells
Cell Size
 All substances that enter or leave a cell must pass
through the surface of the cell
 As a cell gets larger, it takes up more nutrients and
releases more wastes
Cell size is limited by the cells
surface area to volume ratio
 Cells with greater surface – to – volume ratio can
exchange substances more efficiently
Cell features
 All cells have:
 A Cell Membrane
 Cytoplasm
 Ribosomes
 DNA
Cell Membrane
 The cell’s outer boundary
 Acts as a barrier between the cell and its environment
Cytoplasm
 Includes cytosol (fluid inside cell) and almost all the
structures of a cell are suspended in the fluid
 Many ribosomes are found here
Ribosomes
 Cellular structure on which proteins are made
Prokaryotes vs Eukaryotes
 Prokaryote – single celled organism
 Eukaryote – Multicellular organism
Prokaryote
 Contain DNA
 Do not contain a nucleus
 Came before eukaryotes
 First appeared about 3.5 billion years ago
Eukaryotes
 Contain a nucleus that holds DNA
 Organelle – a structure that carries out specific
activities inside the cell
3.
The size to which cells can grow is
limited by their
A. Location
B. Structure
C. Function
D. Surface area to volume ratio
4.One difference between
prokaryotes and eukaryotes is that
prokaryotes do not have
A. DNA
B. A cell membrane
C. Cytoplasm
D. A nucleus
5.
Which cells have a cell membrane,
cytoplasm, ribosomes, and DNA?
A. Only animal cells
B. Only prokaryotic cells
C. Only eukaryotic cells
D. All cells
6.
The genetic material that provides
instructions for making proteins is
A. DNA
B. Cytosol
C. Cytoplasm
D. A ribosome
7.A structure within a eukaryotic cell
that carries out specific activities
inside the cell is called a
A. Organelle
B. Cytoplasm
C. Nucleus
D. Membrane
8.
Which of the following statements
about prokaryotes is correct?
A. They have a nucleus
B. Their evolution preceded that of eukaryotes
C. The organelles in their cytoplasm are surrounded by
membranes
D. They are multicellular organisms
9.
Only eukaryotic cells have
A. DNA
B. Membrane – bound organelles
C. Ribosomes
D. Cytoplasm