BIO U4
Channel Proteins:
allows larger and polar compounds to get into the cell -Small, non-polar compounds (O2, CO2) can pass by the non-polar bilayer directly into the cell
Microscopes
are devices that produce a magnified image of objects too small to be seen with the naked eye.
Resolution
is the the smallest interval distinguishable by the microscope, which then corresponds to the degree of detail visible in an image created by the instrument.
embiosis
one organism living inside another chlorplasts and mitcondria worked together to harnes sunlight and make oxygen and break down sugar using oxyge. ornagians absorbind other organisms was one way species adapted to the chainging envoirment of their surroundings. Endosymbic thoery- how conplex cells evolved. 1. M and C evoleved dthe same way as the ancient bacteria did 2.They both contain their own DNA and ribsoems/ have a circular structure which is very similar to the ancient ones, and very similar genes 3. both have two membrances surrounding them/ inner and outer emembrane. Ther inner membrances contain some particular lipids and proteins that are not present in the outer membrane, because there outer membrance used to tbelong to the blob cell. WEhn they were engulfed in kthe embioss process that got wroapped up in that membrance and kept there own as their inner one explains the orgin of the vast variety of Eurkartic organisms
why cells so small
small cells have a high surface area to volume ratio which allows more stuff to move in and out of the cell
ovarian cell that produces the steroid hormone estrogen
smooth ER
endomembrance system
works together to modify, package, and transport lipids and proteins.
How can we estimate the size of an object under a microscope?
Estimate how many of the object can fit across the diameter, then take the diameter measurement and divide by that number.
Magnification
TOTAL MAGNIFICATION = OCULAR ⨉ OBJECTIVE For example, if the magnifying power of the ocular is 10 (written 10X) and the magnifying power of an objective is 4 (4X), the total magnifying power of the microscope is 40X.
Smooth ER
- The smooth ER is found in both plant and animal cells. - Acts as a storage organelle Help with the synthesis of lipids The smooth ER also stores calcium ions, such as in muscle cells. produces steroid hormones metabolizes carbohydrates
cell theory
1. All living things are composed of cells 2. Cells are the basic units of structure and function in organisms 3. All cells come from other cells
The small size of cells relates to:
1. Efficient control of the cell 2. The need to exchange materials across the plasma membrane
micrograph
A micrograph is a photograph taken through a microscope to show a magnified image of an item. The invention of the electron microscope led to greater understanding of cell structure. Electron microscopes have a much higher resolution than light microscopes so the micrographs they produce will also have higher resolution.
"Animals cells only have mitochondria, plant cells only have chloroplasts"
1st part is true, 2nd part is false - plant cells have mitochondria and chloroplasts
cell membrane
A cell structure that controls which substances can enter or leave the cell.
lysomes
A lysosome is a membranous sac containing digestive enzymes -Very acidic Digests food particles and worn-out organelles Vacuoles Ex: white blood cells - attack bacteria they are rarely found in plant cells, due to the tough cell wall of plant cells that keeps out foreign substances.
Explain why a specimen viewed under the microscope must be thin.
A specimen has to be thin so that the light coming from the light source is able to pass through the specimen. Specimens are sometimes stained with dyes so that they are easier to distinguish and find.
How does the size of a cell affect how efficiently materials get to all parts of a cell?
As an object increases in volume, its surface also increases, but not as quickly. Metabolic rates increase faster than the surface area's ability to exchange materials, therefore a maximum size is reached.
Prokaryotes (bacteria and archaea)
Bacteria are prokaryotic cells Simplest (and smallest) cells No nucleus or organelles One circular chromosome Ribosomes: make proteins Cell (plasma) membrane Contain a non-cellulose cell wall Capsule Projections (flagella) nucleuid
When viewing an object through the high-power objective, why wouldn't all of the object be in focus at the same time?
Because there are different layers within the object on a slide, you are only in focus on one of those layers.
small cell
Cells are small because they are more efficient as smaller entities. Information within small cells is transmitted more quickly and efficiently than within larger cells. have a higher surface area/volume ratios
cell
Cells are the simplest collection of matter that is considered to be alive. discovered in 1665
Smooth ER
Channels through the cytoplasm Smooth ER lacks attached ribosomes Lipid (oils, phospholipid, & steroid) synthesis Ovaries Removal of toxins Liver Storage of Calcium ions Muscles
What are the main functions of the nucleus?
Contains DNA, which makes RNA, which provides the instructions for making proteins Ribosomes read the RNA (instructions) to make/synthesize proteins
The nucleus
Control center of the cell -The genetic instructions of the cell (DNA) are housed in the nucleus. These instructions control what the cell does through directing protein synthesis. -The nucleus is found in all eukaryotic cells no matter whether it is a plant or animal cell. It is located in the central region of the cell in order to be able to perform all its functions with the most efficiency -interacts with other organelles
Explain why we say that the endoplasmic reticulum is a biosynthetic factory.
Creates proteins (digestive enzymes, structural proteins), lipids (hormones, steroids, membrane), etc that the cell needs; Consider biosynthetic factory: "bio" refers to the biological macromolecules in this case proteins/lipids "synthetic" refers to the building of these molecules "factory" refers to the production and manufacturing team (the organelles) that are responsible for synthesis of a protein - ie. DNA/RNA in the nucleus, ribosomes, and ER
estimating specimen size
Estimate the fraction of the field of view that the object occupies. Multiply the FOV diameter by that estimated fraction. For example, if the field of view diameter is 400 μm and the object's estimated length is about one-tenth of that diameter, multiply the diameter by one-tenth to find the object's length.
Cell walls:
enclose, support plant cells
Estimating Specimen Size
In order to estimate the size of the specimen in the field of view, you must first know the size of the FOV diameter; either by direct measurement or calculation.
The Endomembrane System
Includes the nuclear envelope endoplasmic reticulum (ER) Golgi apparatus lysosomes vacuoles the plasma membrane
How is a lysosome like a recycling center?
It contains digestive enzymes and a low pH to help break things down (old organelles, food particles, bacteria, etc) and recycle their molecules
Golgi apparatus
It is found in all plant and animal cells and is located in the cytoplasm of a eukaryotic cell -It is the organelles that builds lysosomes and receives proteins and lipids from the rough ER. -Functions as a factory where proteins, received from the ER, are further processed and stored for transportation to other parts of the celltext. The Golgi apparatus finishes, sorts, and ships cell products.
What is the main advantage of small cell size?
Keeps surface area to volume ratio high so materials can get in and out of cells rapidly; makes transport of materials efficient
Vacuoles
Large vesicles that have a variety of functions including storage Food Vacuoles Contractile (paramecium) Central Vacuole - plants Trash Digestive Pigments Poisons
Eukaryotes (plants and animals cells)
Larger more complex cells containing many organelles -membrane enclosed structures within the cell -Each organelle performs specific functions -DNA is organized into many linear chromosomes --contained inside a membrane-bound nucleus
light microscope
Light microscopes are the most commonly used microscope. Most are "compound" which means they have at least two lenses. Lenses are curved pieces of glass that bend light and can magnify objects. Light is passed through a specimen into the objective lenses, which produces the first magnification. That image is then magnified again by the eyepiece lens.
Only in animal cells Lysosomes Centrioles
Only in plant cells a rigid cell wall Chloroplasts a central vacuole.
Mitochondria
Powerhouse of the cell, organelle that is the site of ATP (energy) production Carry out cellular respiration in nearly all eukaryotic cells Convert glucose and oxygen into carbon dioxide and ATP: the cells energy source
Endosymbiont Theory
Proposes that mitochondria and chloroplasts were formerly small prokaryotes and began living within larger cells
Which of the following cellular structures differ from the other in the list: mitochondrion, chloroplasts, ribosome, lysosome, and vacuole? How does it differ?
Ribosome - not bound by a membrane and therefore not considered an organelle
ribosomes
Ribosomes - protein synthesis - Free ribosomes, Build enzymes - Others attached to the rough Er, Build membrane proteins Example: Pancreas - digestive enzymes, insulin
How are objects oriented under the microscope compared to the naked eye?
Rotated 180° degrees (flipped/inverted over both X- and Y-axis)
Which of the following traces a path of a protein from the site where its polypeptides are made to its export?
Rough ER, Golgi, transport vesicle, plasma membrane
pancreatic cell that secretes digestive enzymes
RoughEr
P vsE
Similarities: both have DNA, cell membrane, ribosomes Differences: presence of nucleus, presence of membrane bound organelles, circular DNA vs linear DNA
vacuoles
Stores food, water, wastes, and other materials
Rough ER
The RER sends proteins to the Golgi apparatus or to outside of the cell membrane Works with ribosomes to create and package proteins -Rough part has ribosomes that create and alter proteins for the whole cell It then packages them and sends them to rest of the cell -eukaryotic cell's in plant and animal organisms
Field of View @ Low Power
The field of view (FOV) is the diameter of the area visible through the microscope. use ruler to measure in mm OK = 4.5 mm NOT OK = 4.50mm
Field of View @ ↑Power
The higher the power of magnification, the smaller the field of view. Diameter LP x Magnification of LP = Diameter of HP x magnification of HP
light vs. electron
The magnification is the same, but the resolution is better with the electron microscope image.
mitocondria
The mitochondria is the powerhouse of the cell. It carries out cellular respiration in almost all eukaryotic cells. They use O2 and release CO2 when they convert chemical energy from food into ATP, which is used for cellular work. Its main function is to create energy to provide for the cell. Present macromolecules include: Proteins (enzymes) Lipids (phospholipids) and Nucleic Acids (RNA) found in plant and animals
Nucleus
The nucleus contains most of the cell's DNA and controls the cell's activities Nuclear envelope -Pores in the membrane allow RNA out of the nucleus Chromosomes -Genetic material (DNA) Contains nucleolus -site of ribosome synthesis
Eukaryotic Cells
The structures and organelles of eukaryotic cells perform four basic functions 1. Genetic Control 2. Manufacture, distribution, and breakdown of molecules 3. Energy Processing 4. Structural support, movement, communication between cells
Lysomes
They also act as the recycling center of cells. -in all animal cells -Lysosomes are digestive enzymes that break down food molecules for digestion. They also release nutrients into . They can also make damaged organelles available for reuse by breaking them down and fixing them. Lysosomes fuse with the food vacuoles and digest them. From there, the nutrients from the food is released into the cytosol.
LIGHT MICROSCOPES
Use lenses to bend light and magnify images Used to study dead or living cells in color Cell movement can be studied
ELECTRON MICROSCOPES
Uses electron beams focused by electromagnets to magnify and resolve. Requires cells to be killed and chemically treated before viewing, so no movement can be seen. Without stain or dye, no color* can be seen. The invention of the electron microscope led to greater understanding of cell structure
The plasma membrane:
a flexible boundary between the cell and its surroundings -Phospholipid bilayer Regulates flow of material in and out of cell
low power use formula
high power divide hp d by hp ratio
Relationship with magnification and FOV
inverse
contrast
is defined as the difference in light intensity between the image and the adjacent background relative to the overall background intensity. A narrow beam provides higher contrast. Staining the specimen may be necessary to obtain the contrast you need to view the details of your sample.
Resotluion
is the smallest interval distinguished by the micrsopt, which the correspondto the defree of deatil visble in an image created by the insturment. a narrow beam provides a higher contrast, increases contrast
Chloroplast
just plant not animal cells Chloroplasts are organelles found in the cells of green tissues of plants and eukaryotic algae consists of phospholipids in the cell membranes, proteins as enzymes, and nucleic acid in the DNA Chloroplasts capture the sun's energy and uses it to produce food for the cell, which then goes to the mitochondria to produce energy that the plant cell can use. Photosynthesizing organelles
cell movements
material moves through cells by diffusion - oxygen and food move into cell, while waste products move out of cells
4x is scanning lowest, 10x is low power, 40x is high power
microsp
eurkatoic is linear
prokaritc Dna is ciruclar
how to find cell size
surface area/ volume some evidence: small cell - 6.2nm, medium cell- .75n, large cell .46nm
cell size
the smaller the cell the more efficent
Ribsomoes
use RNA instructions from the nucleus to build proteins (synthesize proteins) - free ribosomes are suspended to the cytoplasm (sued inside cell) and bound ribosomes are attached to the outside of the ER or envelope -present in plant, animal, and bacterial cells