set 1: preview

Question 1

robert hooke (1665)

Answer 1

• built a microscope that allowed him to see in 30x mag.
• he observed dead cork cells from trees and coined the term “cells”
• known for hooke’s law of elasticity

Question 2

antonie van leeuwenhoek

Answer 2

• dutch merchant, created a microscope that allowed him to see in 300x mag. (more powerful than hookes)
• he was the first to see sperm cells, red blood cells, bacteria, protists.
• called microorganisms “animalcules”

Question 3

Define the term RESOLUTION and how it applies to microscopy.

Answer 3

Minimum distance between 2 objects that can still be distinguished as separate.

Higher resolution = clearer, more detailed image.

Important because magnification without resolution = blurry.

Question 4

Define the term RESOLUTION and why its important as much at magnification.

Answer 4

Resolution is the minimum distance between two objects that can still be distinguished as separate.

High resolution is just as important as magnification because without it, increasing magnification will only make a blurry image larger

Higher resolution = clearer, more detailed image.

Question 5

how do u calculate total mag

Answer 5

total mag= ocular lens x objective lens

Question 6

robert brown (1831)

Answer 6

discovered the nucleus in plants (orchids)

Question 7

matthias schleiden (1838)

Answer 7

concluded that all plant tissues are made up of cells
- embryonic plants arise from a single cell
- co founder of the cell theory

Question 8

Explain the contributions of THEODOR SCHWANN
why was it difficult to visualize animal cell boundaries and SCHWANN’s contributions to the CELL THEORY.

Answer 8

• Concluded (1839) that all animal tissues are composed of cells.
• Challenge: Animal cells lacked rigid walls, so boundaries were harder to see. He used cartilage with collagen to observe distinct cells.
• formulated 2 principals:
  1. all living things are composed of one or more cells
  2. the cell is the basic structural unit of life

Also discovered Schwann cells, which form the myelin sheath around neurons

Question 9

rudolf virchow (1855)

Answer 9

added the 3rd principle: all cells arise from pre existing cells.
- he saw cell division

Question 10

what are the 3 strands of modern cell biology?

Answer 10

1: cytology: study of cell structure (observation of cell physiology)

2: biochemistry: study of cellular function at the molecular level (krebs cycle…)

3: genetics: information flow and heredity (DNA sequencing)

Question 11

Understand that structure of cells often relates to the specific function of the cell.

Answer 11

Cells have diverse forms adapted to their roles:

Neurons → transmit signals (long, branched).

Intestinal villi → absorb nutrients (large surface area).

Filamentous fungi → growth and nutrient absorption.

Question 12

Explain the function of a MICROTOME.

Answer 12

Device to cut specimens into very thin slices (“sections”) for microscopy.

Question 13

Explain the major disadvantage to using stained specimens on bright field microscopes.

Answer 13

kills the specimens

Question 14

Explain the major advantage of using a PHASE CONTRAST MICROSCOPE

Answer 14

enhances contrast in unstained living cells, shows 3D like images

Question 15

Explain the function of a FLUORESCENT MICROSCOPE and be able to explain how this microscope can be used when primary and secondary fluorescent antibodies are used to visualize a cellular sample.

Answer 15

Primary antibody binds to target protein.

Secondary antibody with fluorescent tag binds to primary → emits visible light under excitation.

Allows specific localization of molecules in cells

• A fluorescent microscope allows visualization of specific cellular components by detecting fluorescent dyes. To label a protein, a primary antibody binds specifically to the protein of interest, and a secondary antibody carrying a fluorescent dye binds to the primary. When excited by light, the dye emits fluorescence, enabling the microscope to capture clear, color-coded images of the protein’s location within the cell.

lets you detect specific molecules or dtructures by tagging them with flourencece dye or labes (make al the microtubles in a sell green) or labele the nuclelus blue and mitochondria red. you can see specific things located in a cell

Question 16

Explain the major difference between a FLUORESCENT MICROSCOPE and CONFOCAL MICROSCOPE.

Answer 16

Fluorescent: Shows all labeled structures, including overlapping layers.

Confocal: builds on fluorescent. uses lasers to excite the fluorescent labels but it only collects lights from a single very thin focal plane at a time. then turns it into a 3d image great for looking at thicker tissues.

Captures a single plane of a fluorescently labeled specimen is visualized.

Confocal = clearer depth & localization

Question 17

IMPORTANT: Understand the difference between a TEM and SEM. Know the limit of resolution of a TEM and SEM.
Give examples of biological materials that can be viewed under a TEM and SEM.

Answer 17

Transmission EM (TEM): Electrons passes through the specimen. gives more internal details

Scanning EM (SEM): bounces electrons off the surface. surface of the specimen is scanned. electrons are deflected from the outer surface of the specimen. u see bumps and ridges on the outside of the cells. black and white images.

Resolution: ~0.1–0.2 nm (much better than light microscopy)
Electron microscopes can magnify images
up to 100,000X

SEM - (a) human cancer cell (b) pollen grains
TEM - (c) intestinal cell and (d) mitochondria

Question 18

• Understand why YEAST EXTRACTS are capable of performing fermentation.

Answer 18

Yeast extracts can perform fermentation because they still contain the enzymes to catalyze the breakdown of sugars into ethanol and CO₂.

• This discovery demonstrated that enzymes drive biochemical pathways independently of the whole organism
• ENZYMES FOUND IN CELL EXTRACT RELEASE FROM CELL LYSIS WERE ABLE TO CONVERT GLUCOSE TO PYRUVATE TO ETHONAL

Question 19

List the 3 “strands” of modern cell biology and give at least 2 examples of a laboratory technique that can be used within each strand.

Answer 19

genetics: study of genes, heredity of genes and the variation of inherited characteristics.

Question 20

• Give a brief explanation of the STEPS involved in the SCIENTIFIC METHOD and how the scientific method is applied to answer RESEARCH QUESTIONS.

Answer 20

problem > hypothesis> data collection> interpretation> discussion (accept/reject)