Cells

Question 1

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Cells

Answer 1

• 1665 Robert Hooke used a simple miscroscope to look at cork
• he named the little roomshe observed “cells”

Question 2

Cell theory

Answer 2

1) All organism composed of cells
2) cells are smallest living thing
3) cells arise only from pre-existing cells

Question 3

Cells today represent

Answer 3

• continious line of descent from the living cells
• genetic infromation in each cell in multicellular organism is identical
• multicellular organism can

Question 4

Cell size is limited

Answer 4

• most cells are relaticely small due to reliance on difussion of substances in and out of cells
• rate of diffusion affected by surface Area available
• surface area available
• temperature
• concentration gradient
• distance

Question 5

how do we examine cell?

Answer 5

microscopes

Question 6

not many cells are

Answer 6

• visible to the naked eye
• most are less than 50um in diameter

Question 7

Resolution

Answer 7

minimun distance two points can be apart and still be distinguished as two separate points
- objects must be 100 um apart for naked eye to resolve them as 2 objects rather than one

Question 8

Ligth microscopes

Answer 8

• used magnifying lense with visible light
• resolve structures that are at least 200 nm apart
• resolution is limited by the wave length of light
• ## can magnify cells up yo 1000x

Question 9

Electron Microscopes

Answer 9

• Use beam of electrons
• resolve structures that are 0.1 nm apart
• transmission electron microscopes(TEM)
• transmit electrons through the material
• scanning electron microscopes(SEM) beam electrons onto speciemn surface

Question 10

Basic structural similarities od cells and their componetns

Answer 10

1) nucleoid or nucleus where DNA is located

Question 11

Cytoplasm

Answer 11

• semifluid matrix of organelles and cytosol

Question 12

Ribosomes

Answer 12

• Synthesize protein

Question 13

Plasma mebrane

Answer 13

• Phospholipid bilayer

Question 14

Prokaryotic cells

Answer 14

• Simplest organism
• lack membrane-bound organelles
• DNA is present in the nucleoid
• cell wall outside of plasma membrane (not membrane-bound organelles)
• ## two domains of prokaryotes

Question 15

Bacteria cell walls

Answer 15

• most bacterial cells are encased by a strong cell wall
• composed of peptidoglycan
• cell walla of plants and fungu are different (what are they composed of? review from earlier)
• protect the cell, maintain its shape, and orevent excessive uptake or loss of water
• susceptibility of bacteria to antibiotics often depedns on the structure od their cell walls
• archea lack pepti

Question 16

Flagella

Answer 16

• Represent in some prokaryotic cells
• may have one or more or none
• used for locomotion
• rotary motion propels the cell

Question 17

Eukaryotic cells

Answer 17

-

Question 18

Nucleus

Answer 18

• Repository of genetic information
• most eukaryotic cells possess a single nucleus
• nucleolus-region where ribosomal RNA synthesis takes place
• In eukaryotes, the DNA is divided into multiple linear chromosomes
• chromatin is DNA plus protein

Question 19

Nuclear envelope

Answer 19

• 2 phospholipid bilayer (4 totsl phospholipid sheets)
• nuclear pores-control passage of molecules in and out

Question 20

Ribosomes

Answer 20

• cell’s protein synthhesis machinery
• found in all cell types in all 3 domains
• ribosomal RNA (rRNA)- protein complex
• protein synthesis also requires messenger RNA (mRNA) and transfer RNA (tRNA)
• ## Ribosomes may be free in cytoplasm or associated with internal membranes

Question 21

Endomembrane system

Answer 21

• series of membranes throughout the cytoplasm
• divides cell into compartments where different cellular function
• fundamental distinction between eukaryotes and prokaryotes

Question 22

Endoplasmic reticulum-
Rough endoplasmic reticulum

Answer 22

• attachment of ribosomes to the membrane gives a rough appearance
• synthesis of proteins to be secreted, sent to lysosomes or plasma membrane

Question 23

smooth enfoplasmic reticulum

Answer 23

• Relatively few bound ribosomes
• variety of functions-lipids synthesis, store Ca2+, detoxification
• Ratio of RER to SER depends on cell’s function
• celll that carry out extensive lipid synthesis
  (testes, intestines, brain) = more SER
  Cells that synthesize proteins that are secreted (endocrine cells)= more RER

Question 24

Golgi apparatus

Answer 24

• function in packing and distribution of molecules
• flattened stacks of interconnected membranes (golgi bodies)
• has cis and trans face
• vesicles transport molecules to destination:
• other organelles
• plasma membrane

Question 25

Protein transport through the endomembrane system

Answer 25

1) vesicle contians proteins buds form the rough ER diffise, though the

Question 26

Lysosomes

Answer 26

-membrane-bounded digestive vesicles
low pH enviroment (4.5-5.0)
- arise from golgi apparatus
- enzymes catalyze breakdown of macromolecules
- resulting monomers can be used for subsequence de novo synthesis reactions
- destroy cells or foreign matter that the cell has engulfed by phagocytosis

Question 27

peroxisomes

Answer 27

-membrane bound vesicle
- contain enzymes involved in the oxidation (breakdown) of fatty acids
- Contains enzyme to breakdown toxins such as metabolic waste products, alcohol and drgus
- hydrogen peroxide produced as by-product from cellular reaction reaction- rendered harmless by catalase

Question 28

Vacuoles

Answer 28

• membrane-bounded structures in plants
• various functions depending on the cell type
• there are 3 different types of vacuoles: central vacuole in plants cells (help maintain rigidity)
• contractile vacuole of some fungi and proptists
• storage vacuoles

Question 29

Mitochondria

Answer 29

• Found in al typesof eukaryotic cells
• have their own DNA (genome)!
• Bounded by membrane
• intermembrane space
• inner membrane has cristae
• matrix is the most internal
• Protains that carry out oxidative metabolism are located
• on the surface of the inner membrane
• and embedded within the inner membrane