IB Bio - Quiz 1 - A2.2 - B2.2

Cell Theory(3)

1 - All living things are made of cells

2 - Cells are the smallest/basic units of life/structure/function

3 - Cells come only from existing cells

Unicellular Organisms

Single celled

can carry out all of the functions of life independently

Multicellular organisms(2)

are multi cellular

have specialized cells to carry out specific functions

Organelles(2)

are specialized structures within cells

can’t survive alone

Mitosis

results in genetically identical diploid cells

Meiosis

results in sex cells/haploid gametes

Deductive Reasoning VS Inductive Reasoning

General → Specific Conclusion

Specific → General Conclusion

Microscopes

Instruments that magnify images, allowing for the observation of small structures like cells

Magnification(Def)

The process of enlarging the appearance of an object, calculated using a specific formula

Resolution

ability of a microscope to distinguish details of a specimen or sample

Magnification(Formula)

Mag = Measured Length/Actual Length

Actual Length(Formula)

Actual Length = Measured Length/Mag

Steps to calculate Mag(4)

1 - Measure Scale bar in mm(measure with a ruler)

2 - Convert measured length to um(or whatever length scale bar says)

3 - Note actual length of scale bar(should be in um above/below scale bar)

4 - use formula

Electron Microscopy aka EM(Description and Advantage)

uses electrons to create high-resolution images of specimens

ability to visualize structures at the atomic level, offering far greater detail than light microscopy.

Freeze Fracture(Description and Advantage)

used to examine the ultrastructure of rapidly frozen biological samples, such as plasma membranes.

ability to visualize the arrangement of membrane proteins and lipids with great detail using electron microscopy

Cryogenic Electron Microscopy aka Cryo-EM(Description and Advantage)

Allows scientists to view proteins and other biomolecules which do not readily crystalise.

ability to capture high-resolution images and reduced damage from electron beams

Fluorescent Stains(Description and Advantage)

uses fluorescent dyes to illuminate biological systems, allowing researchers to visualize cellular structures and molecules

ability to selectively highlight and track the presence or distribution of specific molecules or structures within cells

Immunofluorescence(Description and Advantage)

A technique used to visualize specific proteins or antigens in cells or tissues using fluorescently labeled antibodies

able to study the location, distribution, and quantity of specific biomolecules using fluorescent antibodies

Features common to all Cells(4 and Describe)

1 - Plasma Membrane(controls what enters and exits the cell)

2 - Cytoplasm(composed of mainly water, which is where most metabolism occurs)

3 - Ribosomes(protein synthesis - can be different sizes depending on cell)

4 - DNA(genetic material)

Prokaryotic Cells(2)

Cells without membrane-bound organelles

characterized by a nucleoid region containing naked DNA

Naked DNA

DNA not associated with histones

Cell Wall(Prokaryotic)(2)

The cell wall (composed of peptidoglycan) provides the cell with strength and support

It prevents the cell from bursting

Cytoplasm(Prokaryotic)(2)

Most of the metabolism that occurs in the cell occurs here

mostly composed of water.

Plasma Membrane(Prokaryotic)(2)

controls what enters and exits the cell

composed of phospholipids

Ribosomes(Prokaryotic)(2)

70S

responsible for protein synthesis

found in prokaryotes only

Nucleoid Region(3)

contains a single circular chromosome

DNA has no proteins associated with it

DNA responsible for growth and development of the cell

Flagellum

helps cell move

Pilli(2)

allow bacteria to adhere to each other and other surfaces

allow the exchange of genetic material between bacteria

Binary Fission(3)

primary method of reproduction for prokaryotes

asexual reproduction

does not increase variation in population

Eukaryotic Cells

Cells with a nucleus and membrane-bound organelles

ex.animals, fungi, and plants

Plasma Membrane(Eukaryotic)(2)

controls what enters and exits the cell

composed of phospholipids.

Cytoplasm(Eukaryotic)(2)

Most of the metabolism that occurs in the cell occurs here

mostly composed of water.

Ribosomes(Eukaryotic)(2)

80S

responsible for protein synthesis

Nucleus(2)

Chromosomes associated with histone proteins are located here

has a double membrane with pores which allow mRNA to enter the cytoplasm

Chromosomes(Eukaryotic)(2)

Chromosomes are composed of DNA wrapped around histone proteins

The DNA is the genetic material with information for growth and development of the cell

Mitochondria(Eukaryotic)(5)

sight of aerobic respiration

responsible for producing ATP

has double membrane

• outer membrane = smooth

• inner membrane(cristae) = very folded

Vacuoles(Eukaryotic)(2)

Plants have large vacuoles involved in storing nutrients, pushes other organelles to side

Small vacuoles are found in animal cells, and are involved in the removal of waste

Lysosome(Eukaryotic)(2)

Lysosomes are specialised vesicles, which contain enzymes

involved in the digestion of large molecules/cells waste

Rough Endoplasmic Reticulum(Eukaryotic)(3)

membrane structure with ribosomes attached

site of protein synthesis

involved in transporting proteins to the Golgi Apparatus

Smooth Endoplasmic Reticulum(Eukaryotic)(2)

membrane structure without ribosomes attached

involved in lipid synthesis, and detoxification.

Golgi Apparatus(Eukaryotic)

modifies and packages proteins to be exported from the cell

vesicles can be seen around it

Secretory Vesicles

small enclosed membranes

transport proteins from the Golgi Apparatus to plasma membrane

Cytoskeleton(Eukaryotic)(2)

composed of protein microtubules

involved in maintaining cell shape, moving organelles, and nuclear division (mitosis and meiosis).

Centrioles

play a key role in cell division and organization

helps to establish microtubules during cell division

Chloroplast(Eukaryotic)(3)

has a double outer membrane

only found in plant cells

carries out photosynthesis

Microvilli(Eukaryotic)(2)

found on epithelial cells

appear as long finger like extensions of a cell

Prokaryotic VS Eukaryotic Cell(Differences)(9)

Before comma = Pro, After Comma = Eu

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Membrane-Bound Organelles - Not Present, Present

Mitochondria - Not present, Present

Chromosome Location - Nucleiod region in Cytoplasm, Nucleus

# of Chromosomes - 1, Many

Shape of Chromosomes - Loop, Linear

Protein Associated with Chromosomes - None, Histones

Ribosomes - small 70s, large 80s

Cell Wall - made of peptidoglycan, can vary

Cell Size - Smaller, Larger

HEN-GRRMM

Homeostasis

Excretion

Nutrition

Growth

Response to Stimuli

Reproduction

Movement

Metabolism

Homeostasis

process by which living organisms maintain a stable internal environment

Metabolism

complex network of interdependent and interacting chemical reactions occurring in living organisms

Nutrition

processes that organisms use to obtain and use food (nutrients) for growth and development.

Movement

changing of the position of the organism

Excretion

removal of metabolic waste

Growth

increase in mass or size of an organism

Response to Stimuli

ability of organisms to respond to internal or external stimuli

Reproduction

production of offspring

Difference Between Animal, Fungi, and Plant Cells(5)

1st Term = Animal, 2nd Term = Fungi, 3rd Term = Plant

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Cell Wall - Not Present, made of Chitin, made of Cellulose

Vacuoles - Small Scattered vacuoles for storing materials and waste products, small or large vacuoles depending on species, large central vacuoles involved in storing nutrients and waste and maintaining turgor pressure

Centrioles - Present to help in mitosis and meiosis, not present, not present

Plastids - not present, not present, ex. Chloroplasts

Cilia and Flagella - Present in some, not present, not present

Aseptate fungal hyphae

Some fungal hyphae are not separated by septa(internal cell walls), forming one long multinucleate(multi-nucleus) cell.

Skeletal muscle cells

are multinucleate

Red Blood Cells(2)

aka erythrocytes

don’t have a nucleus

Phloem sieve tube

don’t have a nucleus

Endosymbiotic Theory (4)

suggests that all eukaryotes evolved from a common unicellular ancestor

• Engulfment: The host cell engulfs the prokaryote.

• Symbiosis: The engulfed cell benefits the host cell (e.g., energy production) and vice versa.

• Integration: The engulfed cell becomes an integral part of the host, eventually evolving into an organelle(Chloroplast and Mitochondria)

Evidence of Endosymbiotic Theory

Chloroplasts and mitochondria are a similar size to modern prokaryotes and share many characteristics…

• A single circular chromosome with naked DNA.

• 70S ribosomes (larger 80S ribosomes are present in eukaryotic cells cytoplasm) for synthesising proteins.

• Reproducing in the same manner through a process called binary fission

• Have double membrane

Stem Cells(4)

Undifferentiated cells

Capable of differentiating into specialized cells

Capable of endlessly reproducing

genes that are expressed (turned on) determine the structure and function of the specialized cell

Meristematic Tissue

Plant Stem Cells

Cell Organelles

compartmentalized subcellular structures found within a cell, which have a specific functions

Which 3 don’t count as organelles according to ib?(3)

• Cell Wall

• Cytoskeleton

• Cytoplasm

Cell Fractionation(4)

Process to prepare cells for ultracentrifugation

Steps:

• Homogenization: Tissue-containing cells are broken up in a blender

  • The cells are blended in a cold, buffered solution, which is isotonic to the cytoplasm of the cells.

• The blended solution is filtered to remove large cell debris.

Ultracentrifugation(4)

uses a fast centrifuge to separate cell organelles according to density

Steps:

• The filtered solution containing the cell organelles is spun at low speed by an ultracentrifuge

• The densest organelles (nucleus) form a pellet at the bottom of the centrifuge tube

• The pellet is removed, and the process is repeated at faster speeds, producing a series of pellets containing one type of organelle each time

Advantages of compartilized nucleus(3)

• allows for protection of DNA from potentially harmful reactions

• Separates transcription process from metabolism in cytoplasm

• allows for greater cell efficiency