Bio Unit Two Review

What is Cell Theory?

Scientific principle for all living organisms.

1. Composed of one or more cells.

2. All cells come from preexisting cells.

3. Cells are the basic unit of life.

What are the implications of Cell Theory?

• Unicellular organisms must be able to preform all 8 processes of life within their one cell.

• Viruses are cells and not living.

What are prokaryotic cells?

These are single celled organisms that lack a distinct nucleus and other membrane-bound organelles.

What are eukaryotic cells?

A cell that is complex with a nucleus and many other specialized organelles.

What are the 3 different types of eukaryotic cells?

• Animal cells.

• Plant cells.

• Fungal cells.

What type of cell has a cell wall?

Plant cell and fungal cell.

What type of cell has small vacuoles?

Animal and fungal cells.

What type of cell has large vacuoles?

Plant cells.

What type of cell has chloroplasts

Plant cells.

What type of cell has cilia?

Animal cells.

What type of cells have flagella?

Animal and Fungal cells.

What is the cell membrane?

• In every cell.

Thin flexible layer that surrounds every cell, used for: barrier, regulation, communication, and support.

What is the cytoplasm?

• In every cell.

Water-like fluid that fills the inside of the cell to hold organelles in place.

What are ribosomes used for and what size is used for what cell?

To synthesize proteins: read genetic instruction from mRNA to put specific amino acids together.

• 70 s is used in prokaryotic cells.

• 80 s is used in eukaryotic cells.

What is a bound ribosome?

Cellular structure that is attached to the rough endoplasmic reticulum.

• Used to synthesize proteins to be secreted out of the cell.

• Uses mRNA

What are free ribosomes?

Ribosomes that float in the cytosol.

• Composed of rRNA.

• Used for reading genetic material and synthesizing proteins used for the inside of the cell.

What is DNA?

• Genetic material found in all cells.

What is the nucleus and what type of cell is it found in?

• Membrane-bound organelle.

• Eukaryotic cells.

• Stores and protects genetic material within the cell.

What does the nucleolus do?

Produces and assembles the cells ribosomes.

What is the nuclear envelope?

This is the double membrane barrier that surrounds the nucleus within eukaryotic cells.

• Separates the genetic material from the cytoplasm.

What is the nucleoid?

Irregularly shaped, non-membrane-bound region that stores genetic material.

What is naked DNA?

DNA that is free floating.

What are all of the membrane-bound organelles in a eukaryotic cell?

• Nucleus.

• Golgi apparatus.

• Smooth endoplasmic reticulum.

• Rough endoplasmic reticulum.

• Vacuoles.

• Lysosomes.

• Ribosomes.

• Mitochondria.

• Chloroplast.

• Peroxisomes.

• Endosomes.

What is the mitochondria

• Generates ATP energy for the cell.

What is the inner membrane of the mitochondria called?

the cristae.

What are some key features of the mitochondria?

• Double membrane.

• Circular DNA.

What is chloroplast?

Organelle that is only in plant cells that allows for photosynthesis.

What are some key features of chloroplast?

• Double membrane.

• Ribosomes.

• Circular DNA.

What are vacuoles?

Membrane-bound organelle that stores water, nutrients, and waste material.

• Found only in plant cells.

What is a central vacuole?

A giant vacuoles within plant cells that take up a large amount of space.

What is smooth endoplasmic reticulum?

A membrane-bound organelle use for synthesizing lipids and steroids and detoxification in liver cells.

What is rough endoplasmic reticulum?

A membrane-bound organelle filled with ribosomes.

• Used for creating proteins to be secreted out of the cell.

What is the Golgi apparatus?

Locates and sends proteins and lipids to other parts of the cell.

What are vesicles?

A small fluid-filled sack inside the cell used for transportation.

What is a flagella?

A microscopic “tail” outside of some cells used for movement.

• Ex: sperm.

What is a cilia?

Hair-like organelle that is outside of the membrane that protect the surface of the cell.

What are centriosoles?

barrel shaped structures that are made of proteins that help organize the cells skeletal system.

What is compartmentalization?

This is the organization of different cellular activities into specific, membrane-bound regions called organelles.

What are the 8 processes of life?

• Movement.

• Response to stimuli.

• Homeostasis.

• Metabolism.

• Growth.

• Reproduction.

• Excretion.

• Nutrition.

What is the acronym to remember the 8 processes of life?

H.M MR GREN.

Explain the process of life movement.

Living things have some control over their place and position in their environment.

Explain the process of life response to stimuli.

All living things can respond to changes in their external environment.

Explain the process of life homeostasis.

All living things can maintain constant internal conditions, despite changes in their external environment (internal balance).

Explain the process of life Metabolism.

The sum of all chemical reactions inside a living cell that convert food to energy and for building blocks.

Explain the process of life growth.

All cells can increase size over a period of time. In multicellular organism, growth can also refer to an increase in the number of cells that make up an organism.

Explain the process of life reproduction.

All living things can produce an offspring, can be sexual reproduction or asexual reproduction.

Explain the process of life excretion.

All living things must facilitate the removal of their own metabolic waste products.

Explain the process of life nutrition.

Living things must obtain energy and nutrients from their environments.

Why are viruses non-living?

• Cannot reproduce without a host.

• Cannot get their own energy.

• Cannot function without a host.

What are 4 examples of Atypical cells?

• Red Blood Cells.

• Phloem Sieve Tubes.

• Striated Skeletal Muscle.

• Aseptate Fungal Hyphae.

All have Atypical cell structures.

What makes red blood cells Atypical?

They are a eukaryotic cell that do NOT have:

• A nucleus.

• DNA.

They contain hemoglobin storage to carry oxygen around the body.

What is the purpose of phloem sieve tube cells?

To transport organic compounds mainly sugars and amino acids, over long areas of the plant.

What makes phloem sieve tubes Atypical?

These are found in plants cells but what makes them Atypical is that they:

• Have no nucleus.

• Lack many vital organelles such as ribosomes, golgi apparatus, and a standard cytoskeleton.

• Rely on companion cells these cells act as a “life support” system for phloem sieve tube cells.

What is the purpose of striated skeletal muscle cells?

The purpose of these cells is to generate force and contract muscles.

What makes striated skeletal cells Atypical?

They have more than one nucleus per cell.

What is the purpose of aseptate fungal hyphae?

Allow for non-restricted transport of nutrients, water, proteins, and other cellular materials throughout the fungal organism.

What makes aseptate fungal hyphae Atypical?

These are very large cells with multiple nuclei and a continuous cytoplasm (this means that there is no end cell wall or membrane).

What is the endosymbiosis theory?

This is the theory that one eukaryotic cells engulfed a prokaryotic cells and the engulfed cell becomes what is now a mitochondrion or chloroplast.

What was the process of endosymbiosis?

1. Starts with two independent bacteria.

2. One eukaryotic cell engulfed a prokaryotic cell.

3. One bacteria now lives inside the other.

4. The internal bacteria ate passed on from generation to generation.

What are the four different pieces of evidence for endosymbiosis?

• Double membrane.

• Naked and circular DNA.

• 70 s ribosomes.

• Replicate independently from the rest of the cell.

How is the double membrane a piece of evidence for endosymbiosis?

• The inner membrane was the original cell membrane.

• The outer membrane was created during the engulfment process.

How is naked and circular DNA a piece of evidence for endosymbiosis?

• Prokaryotic cells contain a single loop of circular DNA.

• Mitochondrial and chloroplast DNA contain similar genes to other prokaryotes.

How is 70 s ribosomes a piece of evidence for endosymbiosis.

• Ribosomes found in the cytoplasm of a eukaryotic cell are 80 s.

• Ribosomes found in mitochondria and cholorplast are 70 s similarly to prokaryotes.

How is mitochondrial and chloroplast replicating independently from the rest of the cell a piece of evidence to support endosymbiosis.

• They replicate independently in a way that is similar binary fission (just how prokaryotes do).

What is pre-biotic/early earth?

This is some of the earliest idea of how earths conditions used to be.

• This describes earth’s atmosphere lacking oxygen and the ozone had an abundance of CO2 and methane.

  • Without the ozone more UV light could reach the surface of the earth.

What experiment attempted to replicate early earth?

Miller-Urey Experiment.

• They attempted to mimic early earth and create a new biological molecules.

• They used gases such as H20, CH4, NH3, and H2.

• They created amino acids.

• In this context organic meant molecules that contain carbon.

What is primordial soup?

This is a hypothetical mixture of water and organic compounds that existed on earth billions of years ago.

What is a spherical bilayer for the formation of vesicles?

• In aqueous environments fatty acids will spontaneously self assemble to form a spherical bilayer.

  • These spherical bilayers form a membrane that separates internal environments to external environments.

What is the Last Universal Common Ancestor (LUCA) and what is two pieces of evidence that support LUCA?

This shared ancestor was likely a unicellular, autotrophic, microbe that existed between 2.5 to 3.5 billion years ago.

• Evidence that supports LUCA is:

  • The universal genetic code.

  • Conserved genes across all organisms.

What is a hydrothermal vent?

This is the area that fossilized evidence has shown us that LUCA could have evolved around.

• Hydrothermal vents remain a hotbed of life today.

• Organisms thrive in the mineral rich environment that is surrounding the vents.

What does selective permeability mean?

This is a membrane that allows certain molecules or ions to pass through it while blocking or restricting others.

• This is done in the phospholipid bilayer because of the hydrophobic tail region of the bilayer.

What is a molecule type that is permeable?

Non-polar and small molecules.

What is a molecule type that is mostly permeable?

Uncharged, small, polar molecules.

What is a molecule type that is mostly impermeable?

Uncharged, large, polar molecules.

What is a molecule type that is impermeable?

Ions.

What are membrane proteins?

Proteins that are embedded or attached to the phospholipid bilayer of a cell membrane.

What are the two types of membrane proteins?

• Integral.

• Peripheral.

What are integral proteins?

These are proteins that are permentaly attached or embedded in the phospholipid bilayer within the biological membrane.

What are transmembrane integral proteins?

These are integral proteins that span the width of the bilayer and can help in transporting materials across the membrane.

• These proteins are amphipathic.

What are peripheral proteins?

These are proteins that attach temporarily on the phospholipid bilayer and not embed in the hydrophobic inner core.

• Hydrophilic.

What are the 5 functions of membrane proteins?

• Transport.

• Receptors.

• Enzymes.

• Recognition.

• Adhesion.

Explain what membrane proteins is needed for transport.

Transport proteins must be transmembrane in order to effectively transport materials across the bilayer.

Explain how membrane proteins function to help cell recognition.

• Membrane proteins on the extracellular side of the bilayer serve as “ID tags” for cell-to-cell recognition.

Important element of immune system: recognizing “self” vs”non-self” cells.

Explain how membrane proteins function to help cell receptors.

• Membrane proteins receive chemical signals when molecules bind to receptors proteins.

• This often causes a signal transduction.

Explain how membrane proteins function to help enzymes.

They catalyze reactions.

Explain how membrane proteins function to help adhesion.

Often cells within the same tissue are joined together by membrane proteins connecting together.

• Can be temporary or permanent.

What are glycoproteins and glycolipids?

These are carbohydrate chains (oligosaccharides) linked to lipids (glycolipids) or proteins (glycoproteins)

What are oligosaccharides?

These are a type of carbohydrate which is formed by 3-10 monosaccharides which are linked together.

What are the 4 functions of glycolipids and glycoproteins and how does it work?

• Recognition: carbohydrate chains act as ID tags.

• Adhesion: carbohydrate chains bind to chains on other cells.

• Signaling: receptors for chemical messengers.

• Protection: carbohydrate groups create a “sticky” later on extracellular surface - this is called glycocalyx.

What does glycocalyx do?

It creates a protective layer for the cell surface.

Why are glycoproteins are conjugated proteins?

Glycoproteins are conjugated proteins because they have non-protein parts.

What is the extracellular side of a membrane?

This is the outer face of the plasma membrane that is directed toward the outside of the cell and exposed to the surrounding environment.

What is cholesterol?

• A steroid found in animal cells.

• Amphipathic.

What is the function of cholesterol?

• At low temperatures cholesterol prevents the fatty acid chains of the phospholipids from fitting closely together, preventing the tendency of the membrane to freeze.

• At high temperatures cholesterol stabilizes the membrane and reduces the membrane fluidity.

• It decreases the permeability of the membrane to some solutes.

What is cholesterol’s impact on membrane fluidity?

• At high temperatures fluidity decreases.

• At low temperatures fluidity increases.

Where is cholesterol located on the phospholipid bilayer?

Within the hydrophobic tails.

What is membrane fluidity?

Because the bilayer is viscous, the phospholipids move and flow around each other.

What are 4 factors that impact membrane fluidity?

• Fatty acid length.

• Fatty acid saturation.

• Cholesterol.

• Temperature.

How does fatty acid length impact membrane fluidity?

Shorter fatty acid tails increase fluidity.

How does fatty acid saturation impact membrane fluidity?

Unsaturated fats because of their kinks make it harder to pack together and have a lower melting point compared to saturated fatty acids.