Cell theory (CH 4.1)

Question 1

Who was the first person to observe cells?

Answer 1

• Robert Hooke in 1655

- Named shapes he saw in cork Cellulae (small rooms)

Question 2

Who was the first person to observe LIVING cells?

Answer 2

• Anton Van Leeuwnehoek

- Termed “animacules”

Question 3

What are 3 principles of Cell Theory?

Answer 3

• All organisms are composed of one or cells &; life processes of metabolism &’ heredity occur within these cells
• Cells are the smallest living things= basic units of organization of all organisms
• Cells come from the division of previous cells

Question 4

Why are cells so small?

Answer 4

-Reasons related to diffusion of substances in &; out of them

Question 5

What variables affect the rate of diffusion?

Answer 5

• Surface area
• Temperature
• Concentration gradient of diffusion subject
• Distance over where diffusion must occur

Question 6

What is the relationship between the size of the cell &; diffusion?

Answer 6

• Directly proportional
• The bigger the cell, the longer the length of time for diffusion from outside of cell membrane to inside of cell
• Larger cells need to synthesize more macromolecules= higher energy needed= higher waste produced

Question 7

What does the rate depend on between metabolic waste being removed &; transport through cell membrane?

Answer 7

-Distance of cell membrane &; the area of cell membrane available

Question 8

What is Surface-Area to Volume Ratio?

Answer 8

• As cell size increases, it’s volume increases more rapidly than the surface area
• For spherical cells, surface area= Radius^2 &; volume= Radius ^3

Question 9

Why are smaller cells better than bigger cells?

Answer 9

-Have more surface area per unit of volume= control of contents over contents is more effective

Question 10

What is Resolution?

Answer 10

-Minimum distance between two points can be apart &; still be distinguished as two separate points

Question 11

How do Modern Light Microscrope operate?

Answer 11

• Operate w/ visible light
• Use 2 magnifying glasses to achieve high magnification &; clarity
• 1st lense= focuses image of the 2nd lens &; magnifies it &; focuses on the back of the eye

Question 12

What causes images from a microscope to overlap?

Answer 12

• Objects being closer than a few hundred nanometers

- Light beams reflecting off the object causes the image to overlap each other

Question 13

How do you reduce overlapping of images for a microscope?

Answer 13

-Using electron beams because they have a shorter wavelength= has 1000x more power than a light microscope

Question 14

What are the 2 kinds of electrons microscopes?

Answer 14

• Transmission electron microscope

- Scanning Electron Microscrope

Question 15

What is Immunohistochemistry?

Answer 15

• Strains that bind to particular types of molecule to increase constrast between different cellular components
• Using antibodies generated in animals

Question 16

What are the 4 major features that all cells have in common?

Answer 16

• Nucleoid/ Nucleus where genetic material is stored
• Cytoplasm
• Ribosomes to synthesize proteins
• Plasma membrane

Question 17

Where does DNA lie in Prokaryotes?

Answer 17

-Lies in the center of the cell= Nucleoid (not segregates from rest of the interior membrane

Question 18

Where does DNA Eukaryotes?

Answer 18

-Contained in nucleus= surrounded by double-membrane structure= Nuclear Envelope

Question 19

What is a Cytoplasm?

Answer 19

• Contains all sugars, amino acids, proteins the cell uses to carry out its everyday activities
• More like jell-o bc it has a high concentration of proteins &; other macromolecules

Question 20

What are Organelles?

Answer 20

• Macromolecular structures that have their own specialized function
• Located in cytoplasm

Question 21

What is Cytosol?

Answer 21

• It’s the part of the cytoplasm that contains organic molecules &; ions in the solution
• Distinguishes it from the organelles in the cytoplasm

Question 22

What is a Plasma Membrane?

Answer 22

• Phospholipid bilayer 5-10nm thick
• Has proteins embedded in it
• Tail to Tail packing

Question 23

What are the different types of proteins & what are their jobs?

Answer 23

• Responsible for cell’s ability to interact w/ environment
• Transport Proteins= helps ions &; molecules move across membrane
• Receptor Proteins=Induce changes within the cell when they come in contact w/ specific molecules which can function as markers that identify the cell as a particular type

Question 24

What are the 6 (or 5) features of life?

Answer 24

• Complex organization
• Responds to external environment
• Maintains internal environment (homeostasis)
• Carries out metabolism & growth (energy metabolism using ATP)
• Reproduces & maintains heredity which leads to
• Adaptation to environment & evolves

Question 25

What does Cell theory explain?

Answer 25

- Our definition of life - Cells provide complexity, organization, responsiveness, homeostasis, metabolism, & growth - Explains continuity features= Reproduction, heredity, adaptation to environment & evolution

Question 26

What is the size range for a cell?

Answer 26

-1 micrometer to 1 nm (100 fold change)

Question 27

Why is the size range of a cell size ideal?

Answer 27

- If it's too small (smaller than 1 micrometer)= not enough room for molecules especially DNA= hard to keep life going - If its too big= has to much waste to export & has to import hella food which is based on the volume of the cell & there isn't enough surface area

Question 28

What are the special exceptions to the cell size range & why?

Answer 28

- Eggs! | - Bc they are filled with the materials needed by the special mechs

Question 29

What is the difference between Eukaryotes & Prokaryotes?

Answer 29

- Euks= have membrane-bound nucleus & internal membrane system - Prokary= don't have nucleus & internal membrane system

Question 30

What are considered to be Non-living & why?

Answer 30

- Viruses, individual molecules, & individual organelles | - Organelles can keep working after they've been separated from the cell