Unit 2 Breadcrumbs (vocabulary focused)

Flashcards on breadcrumbs

What is the basic unit of structure and function?

Cell

What happens when cells increase in volume?

As cells increase in volume, the surface area-to-volume ratio decreases, and the exchange of materials becomes less efficient. T

Surface area-to -volume ratio applied to organisms

The surface area-to-volume ratio concept can also be applied to organisms. As organisms increase in size, their ratio will decrease and this can affect properties of the organism, such as heat-exchange with their surroundings. Small organisms lose heat at much higher rates than larger organisms as a result of their efficient exchange of heat.

What are light microscopes used for?

They are used to study stained or living cells.

How many times can they magnify the size of an organism?

They can magnify the size of an organism up to 1,000 times.

What are electron microscopes used for?

They are used to study detailed structures of a cell that cannot be easily seen or observed by light microscopy.

What are the two distinct types of cells?

Prokaryotic cells and Eukaryotic cells.

Examples of prokaryotes

Bacteria and archaea

Prokaryotes

a lot smaller and simpler than eukaryotic cells

The genetic material in a prokaryotic cell is…

one continuous, circular DNA molecule that is found free in the cell in the nucleoid

Most prokaryotic cells have a…

cell wall composed of peptidoglycans that surrounds a lipid layer called the plasma membrane.

What is cytoplasm?

The substance that the inside of the cell is filled with.

Do prokaryotes have ribosomes?

Yes, prokaryotes also have small ribosomes.

What do some bacteria may have?

Some bacteria may also have one or more flagella, which are used for motility and they might have a thick capsule outside their cell wall for extra protection.

Do prokaryotes have membrane-bound organelles?

Prokaryotes do not have any membrane-bound organelles. Their only membrane is the plasma membrane.

Eukaryotic cells

Are more complex and larger than prokaryotic cells.

Examples of eukaryotic cells

Fungi, protists, plants, and animals.

What are the small structures in eukaryotes?

Eukaryotic cells have many smaller structures called organelles. Some of these organelles are the same structures seen in prokaryotic cells, but many are uniquely eukaryotic.

What is the plasma membrane?

It is the outer envelope of the cell, made up of mostly phospholipids and proteins.

Why is the plasma membrane important?

The plasma membrane is important because it regulates the movement of substances into and out of the cell. The membrane is semipermeable.

What proteins are associated with the plasma membrane? Where are they located?

Many proteins are associated with the cell membrane. Some of these proteins are loosely associated with the lipid bilayer (peripheral proteins). They are located on the inner or outer surface of the membrane.

What are amphipathic pto

Others are firmly bound to the plasma membrane (integral proteins). These proteins are amphipathic.

What are transmembrane proteins?

Some integral proteins extend all the way through the membrane (transmembrane proteins).

What is the fluid-mosaic model?

This arrangement of phospholipids and proteins is known as the fluid- mosaic model.

What do adhesion proteins do between adjacent cells?

Adhesion proteins form junctions between adjacent cells.

What do receptor proteins serve as?

Receptor proteins such as hormones, serve as docking sites for arrivals at the cell.

What do transport proteins do?

Transport proteins form pumps that use ATP to actively transport solutes across the membrane.

What do channel proteins do?

Channel proteins form channels that selectively allow the passage of certain ions or molecules

What are cell surface markers?

Cell surface markers such as glycoproteins, and some lipids, such as glycolipids, are exposed on the extracellular surface and play a role in cell recognition and adhesion.

Where are carbohydrate side chains found?

Carbohydrate side chains are found only on the outer surface of the plasma membrane.

What is usually the largest organelle in the cell?

The Nucleus

What is the nucleus home to?

It’s the home of the hereditary information—DNA

What is DNA organized into?

organized into large structures called chromosomes

What is the nucleus’s purpose?

Direct whats going on in the cell and is responsible for the cells ability to reproduce

What is the most visible structure in the nucleus?

The nucleolus

What happens in the nucleolus?

rRNA is made and ribosomes are assembled.

What are the sites of protein synthesis?

The ribosomes are sites of protein synthesis.

What is the ribosomes job?

Their job is to manufacture all the proteins required by the cell or secreted by the cell.

What is the structure of the ribosome?

Ribosomes are round structures composed of two subunits, the large subunit and the small subunit.

What is the structure of a ribosome composed of?

The structure is composed of ribosomal RNA (rRNA) and proteins.

Where are ribosomes located?

Ribosomes can be either free floating in the cell or attached to another structure called the endoplasmic reticulum (ER)

What is the ER’s structure?

The ER is a continuous channel that extends into many regions of the cytoplasm and provides mechanical support and transportation.

What does the rough ER do to the cell?

The rough ER compartmentalises the cell.

What is the smooth ER?

The region of the ER that lacks ribosomes is called the smooth ER.

What does the smooth ER do?

The smooth ER makes lipids, hormones, and steroids and breaks down toxic chemicals.

What is the rough ER’s function?

The rough endoplasmic reticulum (rough ER) is an organelle in eukaryotic cells responsible for producing and processing proteins. It's called "rough" because it's covered with ribosomes, which build proteins based on genetic instructions. These proteins are then folded and modified inside the rough ER before being sent to the Golgi apparatus for further processing or export from the cell.

What does the golgi apparatus do?

After the ribosomes on the rough ER have completed synthesizing proteins, the Golgi complex modify, process, and sort the products.

What is the golgi complex?

They’re the packaging and distribution centers for materials destined to be sent out of the cell. They package the final products in little sacs called vesicles, which carry products to the plasma membrane.

What is the mitochondria?

They’re power stations responsible for converting energy from organic molecules into useful energy for the cell. The most common energy molecule in the cell is adenosine triphosphate (ATP).

What is the structure of the mitochondria?

It consists of an inner portion and an outer portion. The inner mitochondrial membrane forms folds known as cristae and separates the innermost area (the matrix) from the inter-membrane space. The outer membrane separates the inter-membrane space from the cytoplasm.

What do lysosomes have?

They have sacs that carry digestive enzymes, which they use to break down old, worn-out organelles, debris, or large ingested particles.

When are lysosomes made?

Lysosomes are made when vesicles containing specific enzymes from the trans Golgi fuse with vesicles made during endocytosis.

What is something lysosomes are essential for?

Lysosomes are also essential during programmed cell death called apoptosis.

What are vacuoles?

They are fluid-filled sacs that store water, food, wastes, salts, or pigments.

What are vacuoles functions?

Vacuoles are membrane-bound organelles that store water, nutrients, and waste products in cells. In plant cells, the large central vacuole helps maintain structure by keeping turgor pressure. Vacuoles also help with waste breakdown, pH balance, and sometimes defense by storing harmful substances.

What are peroxisomes?

Peroxisomes are organelles that detoxify various substances, producing hydrogen peroxide (H2O2) as a byproduct.

What do peroxisomes have?

They have enzymes that break down hydrogen peroxide into oxygen and water.

What is the shape of a cell determined by?

The shape of a cell is determined by a network of protein fibers called the cytoskeleton.

What are the most important fibers of cytoskeletons?

The most important fibers are microtubules and microfilaments.

What are microtubules made up of?

Microtubules are made up of the protein tubulin

What do microtubules participate in?

participate in cellular division and movement.

What are microfilaments important for?

Microfilaments are important for movement.

What are microfilaments composed of?

These thin, rodlike structures are composed of the protein actin. Actin monomers are joined together and broken apart as needed to allow microfilaments to grow and shrink.

What do cilia and flagella have in single-celled organisms?

Cilia and flagella have locomotive properties in single-celled organisms.

What allows cilia and flagella structures to move?

The beating motion of cilia and flagella structure allows it to move.

What is a cell wall?

Plant cells, unlike animal cells, have a cell wall (made of cellulose). A cell wall is a rigid layer just outside the plasma membrane that provides support for the cell.

What do plant cells posses that animal cells dont?

Plant cells possess chloroplasts, which have a double outer membrane.

What do chloroplasts contain?

Chloroplasts contain chlorophyll, which gives plants their characteristic green color.

What is the cytoplasm usually taken up by in a plant cell?

Cytoplasm within a plant cell is usually taken up by a large vacuole which is the central vacuole.

What don’t plant cells have that animal cells do?

Plant cells also differ from animal cells in that plant cells do not contain centrioles.

What do the ability of molecules to move across the cell membrane depend on?

The ability of molecules to move across the cell membrane depends on:

1. the semipermeability of the plasma membrane

2. the size and charge of particles that want to get through

What is facilitated transport?

When the diffusion requires the help of a channel-type protein, it is called facilitated diffusion.

What is simple diffusion?

When the molecule that is diffusing is hydrophobic, the diffusion is called simple diffusion because the small non-polar molecule can just drift right through the membrane without trouble.

What is passive transport?

Anytime that a substance is moving by diffusion, it is called passive transport because there is no outside energy required to power the movement.

What are aquaporins?

Aquaporins are water-specific channels

What else is transported across the membrane via membrane proteins?

Glucose and ions such as Na+ and K+ are also transported across the plasma membrane via membrane proteins. Membranes may become polarised as these ions move across them.

What is diffusion?

If there is a high concentration of something in one area, it will move to spread out and diffuse into an area with a lower concentration. The substance moves down a concentration gradient. This is called diffusion.

What is the difference between osmosis and diffusion?

The only difference is that in diffusion the membrane is usually permeable to solute, and in osmosis it is not.

Whys is the cell wall important in plant cells?

In plants, the cell wall is important to protect it against osmotic changes, while the cell membrane can shrink away from the wall (a process called plasmolysis) if it loses water and can expand and squeeze tightly against the cell wall if it takes in water.

What is tonicity used to describe?

Tonicity is used to describe osmotic gradients.

What is tonicity?

Tonicity refers to how the concentration of solutes outside a cell compares to the concentration inside the cell, which affects the movement of water across the cell membrane.

(Isotonic, hypertonic, and hypotonic)

What does isotonic mean?

If an environment is isotonic to the cell, the solute concentration is the same inside and outside.

What does hypertonic mean?

If an environment is hypertonic to the cell, the solute concentration is less inside and more outside.

What does hypotonic mean?

If an environment is hypotonic to the cell, the solute concentration is the more inside and less outside.

What is water potential?

Water potential (Ψ) is the measure of potential energy in water and describes the eagerness of water to flow from an area of high water potential to an area of low water potential.

What is osmosis affected by?

It is affected by: pressure potential (Ψp) and solute potential (Ψs)

What is solute potential of a solution?

Solute Potential of a Solution Ψs = −iCRT where: i = ionization constant C = molar concentration R = pressure constant T = temperature in Kelvin (°C + 273)

What happens when you add a solute to a solution?

Adding a solute lowers the water potential of a solution, causing water to be less likely to leave this solution and more likely to flow into it. The more solute molecules present, the more negative the solute potential is.

What is movement against the natural flow called?

Movement against the natural flow is called active transport.

Some proteins in the plasma membrane are powered by…

Some proteins in the plasma membrane are powered by ATP.

An example of active transport.

An example of active transport is a special protein called the sodium-potassium pump. It ushers out three sodium ions (Na+) and brings in two potassium ions (K+) across the cell membrane. This pump depends on ATP to get ions across that would otherwise remain in regions of higher concentration.

When does primary active transport occur?

Primary active transport occurs when ATP is directly utilised to transport something.

When does secondary active transport occur?

Secondary active transport occurs when something is actively transported using the energy captured from the movement of another substance flowing down its concentration gradient.

What is endocytosis?

When the particles that want to enter a cell are just too large, the cell uses a portion of the cell membrane to engulf the substance. The cell membrane forms a pocket, pinches in, and eventually forms either a vacuole or a vesicle. This process is called endocytosis.

What are the three types of endocytosis?

Three types of endocytosis : pinocytosis, phagocytosis, and receptor- mediated endocytosis.

What does pinocytosis do?

the cell ingests liquids.

What does phagocytosis do?

The cell takes in solids.

What does receptor-mediated endocytosis do?

involves cell surface receptors that work in tandem with endocytic pits that are lined with a protein called clathrin. When a particle, or ligand, binds to one of these receptors, the ligand is brought into the cell by the invagination, or “folding in” of the cell membrane. A vesicle then forms around the incoming ligand and carries it into the cell’s interior.

What is bulk flow?

Bulk flow is the one-way movement of fluids brought about by pressure.

Examples of bulk flow

Example: movement of blood through a blood vessel and the movement of fluids in xylem and phloem of plants are examples of bulk flow.