Unit 4: Cells

Question 1

Cell Theory

Answer 1

1. All living things are made up of cells
2. Sells are the basic units of structure and function
3. New cells are produced by existing cells

Question 2

mirograph

Answer 2

a photo taken through a microscope

Question 3

Robert Hook

Answer 3

• 1665 = he used an early compound microscope to look at a thin slice of cork (plant material)
• he noted that the chambers looked like cells of a monastery

Question 4

Anton van Leeuwenhoek

Answer 4

• 1st to observe living cells in pond water

- 1st to observe and describe bacteria

Question 5

Matthias Schleiden

Answer 5

-1838 = concluded that all plants are made up of cells

Question 6

Theodor Schwann

Answer 6

-1839 = stated that all animals are made up of cells

Question 7

Rudolph Virchow

Answer 7

-1855 = concluded that new cells were created only from the division of existing cells

Question 8

electron microscopes

Answer 8

• reveal details 1,000 times smaller than those visible in light microscopes
• uses a beam of electrons instead of light

Question 9

election microscopy

Answer 9

-used to see only non-living preserved cells and tissues

Question 10

transmission electron microscopes (TEMs)

Answer 10

• used to study cell structures, large protein molecules, and the details of internal cell structure
• specimen must be cut into ultra thin slices and are stained with atoms of heavy metals, which attach to certain cellular structures more than others
• uses a beam of electrons
• they have truly revolutionized the study of cells and their structures

Question 11

scanning electron microscopes (SEMs)

Answer 11

• produce 3D images of cells
• used to study detailed architecture if cell surfaces
• specimen don’t have to cut into thin slices

Question 12

Prokaryotes

Answer 12

• unicellular
• cells don’t have nuclei
• have genetic material that isn’t contained in a nucleus
• doesn’t have membrane-bound organelles
• all are considered a type of bacteria (archeabacteria, eubacteria)
• generally smaller and simpler than eukaryotic cells

Question 13

Eukaryotes

Answer 13

• cells have nuclei
• the nucleus is where their genetic material is separated from the rest of the cell
• generally larger and more complex than prokaryotic cells
• mostly multicellular
• generally contain dozens of structures (organelles) and internal membranes
• Ex: plants, animals, fungi, protists
• highly specialized due to organelles

Question 14

Endosymbiosis

Answer 14

• theory that suggests that certain organelles were once free-living organisms
• it explains that origins of eukaryotic cells
• Evidences = mitochondria and chloroplasts have prokaryotic ribosomes and both copy themselves from cells; Each contains circular pieces from DNA like prokaryotes

Question 15

Cells

Answer 15

• a basic unit of living matter separated from its environment by a plasma membrane
• they are the fundamental structural unit of live
• come in a variety of shapes and sizes
• all cells are surrounded by a barrier called a cell membrane and at some point contain DNA
• cells are classified into 2 categories depending on whether they contain a nucleus

Question 16

nucleus

Answer 16

-large membrane-enclosed structure that contains the cell’s genetic material in the form of DNA and it contains many of the cell’s activities

Question 17

organelles

Answer 17

• “little organs”
• in the cytoplasm
• a membrane-enclosed structure with a specialized function within a cell
• the evolution of organelles creates a division of labor where every organelle had it’s own job

Question 18

light microscopes (LM)

Answer 18

• works by passing visible light through a specimen (microorganism or thin slice of animal tissue)
• the glass lenses in it bend the light to magnify the image of the specimen and project the image into the viewer’s eye or onto photographic film or a video screen

Question 19

magnification

Answer 19

-the increase in the apparent size of an object

Question 20

cytoplasm

Answer 20

-the entire region between the nucleus and the plasma membrane

Question 21

nucleoid

Answer 21

• where the DNA of a prokaryotic is coiled

- inside the nucleus

Question 22

ribosomes

Answer 22

-tiny structures that make proteins according to the instructions from the genes (DNA)

Question 23

chromosomes

Answer 23

• a threadlike,gene-carrying structure found in the nucleus of a eukaryotic cell and most visible during mitosis and meiosis
• the main gene-carrying structure of a prokaryotic cell
• they consist of chromatin and a combo of DNA and protien
• carry genes made of DNA

Question 24

flagella

Answer 24

• long projections/cellular appendages
• may propel the prokaryotic cell through its liquid environment
• specialized for locomotion (movement or ability to move from one place to another)
• the flagella of prokaryotes and eukaryotes differ in structure and function
• eukaryotic flagella have a 9+2 arrangement or microtubules covered by the cell’s plasm membrane

Question 25

pili

Answer 25

• short projections

- help attach prokaryotes to surfaces

Question 26

plasma membrane

Answer 26

• membrane that sets a cell off from its surroundings and acts as a selective barrier to the passage of ions and molecules into and out of the cell (active and passive transport)
• consists of a phospholipid bilayer in which are embedded molecules of protein and cholesterol

Question 27

the 4 basic functional groups the structures and organelles of eukaryotic cells can be organized into

Answer 27

1. the nucleus, ribosomes, enoplasmic reticulum, and Golgi apparatus function in manufacturing
2. organelles involved in breakdown or hydrolysis of molecules include lysosomes, vacuoles, and peroxisomes
3. mitochondria in all cells are involved in energy processing
4. structural support, movement, and communication among calls are functions of components of the cytoskeleton, plasm membrane and cell wall

Question 28

cellular metabolism

Answer 28

the chemical activities of cells

Question 29

lysosomes

Answer 29

• digestive organells in eukaryotic cells

- contains hydrolytic enzymes that digest the cell’s food and wastes

Question 30

vacuoles

Answer 30

• membrane-enclosed sac that is part of the endomembrane system for a eukaryotic cell
• has diverse functions

Question 31

peroxisomes

Answer 31

-organelle consisting of enzymes that transfer hydrogen from various substrates into oxygen, producing and then degrading hydrogen-peroxide

Question 32

centrioles

Answer 32

• structure in an animal cell made up of cylinders of microtubule triplets arranged in a 9 and 0 pattern
• an animal usually has a centrosome with a pair of centrioles involved in cell division

Question 33

plasmodesmata

Answer 33

-channels through cell walls that connect adjacent cells

Question 34

chloroplast

Answer 34

• where photosynthesis occurs in plant cells

- gives plants green color

Question 35

cytoskeleton

Answer 35

• network of protein filled fibers in the cytoplasm of a eukaryotic cell
• includes microfilaments, intermediate filaments, and microtubes (and ribosomes)
• keeps the structure of the cell