Unit 3 - Cytology

Mitosis, Cell Cycle, Cell Transport, Cell Types, Cell Membrane,

What is the name for an occurance where cells divide and multiply uncontrollably?

Cancer.

Why do cells divide?

To form new cells(as in new types), regeneration, and reproduction

Preparation phase of Mitosis? What crucial events happen?

Interphase. During interphase, the cell grows, duplicates its DNA, and prepares for mitosis. This phase is crucial for ensuring that each daughter cell receives an identical set of chromosomes.

First phase of Mitosis? What crucial events happen?

Prophase. Chromosomes become visible, Nucleolus disappears, the Nuclear envelope breaks down, and centrioles separate and take position on either side of the nucleus

What is a centriole?

A centriole is the organelle that forms the centrosomes, which are the places where the spindle fibers are attached to. The centrosomes are formed at a 90 degree angle.

Second phase in Mitosis? What crucial events happen?

Metaphase. The chromosomes line up across the center of the cell and the spindle fibers attach to the centromeres of the chromosomes.

Where are centromeres located?

In the constricted region of the chromosomes; it is the point of attachment of the spindle fibers to the chromosomes.

Third phase of mitosis? What crucial events happen?

Anaphase. The chromatids separate during this phase and they are turned into individual chromosomes. After, spindle fibers pull these chromatids to the end of the cell, or the centrosomes.

What are the two chromosomes called after they are copied in the Interphase?

They are called chromatids.

Fourth stage of Mitosis? What crucial events happen?

Chromosomes unravel into chromatin, a nuclear envelope reforms around each cluster of chromosomes, the spindle breaks apart, and the nucleolus becomes visible in each daughter cell

What is the final process’s name and what events happen? What is changed for plant cells in this process? (Hint: it happens at the same time as the telophase)

It’s name is cytokinesis, and it is when the cell divides into two daughter cells, the cell membrane pinches inward, and the cytoplasm divides. A cell plate forms instead of a cell wall in plant cells.

What is special about stem cells? What specific thing has to be expressed in order to fulfill this?

They are the foundation for all other cells, in a way. They have the potential to be any type of cell (skin, digestive, blood, etc.) depending on which genes are expressed in the DNA segment.

What is gene expression?

What is gene regulation? How is it started?

Gene regulation is when certain genes are turned on/off in different types of cells. It is managed by internal and external cues.

What is a special characteristics that are a result of cancer? What factors make cells more prone to cancer?

Cells do not respond to the signal that regulates the growth of most cells. Some factors are genetic mutations, excessive UV exposure, radiation, or toxins

Mitosis splits a cell into ___ parts…

2

How does a cell make sure it makes an exact copy in Mitosis? (Hint: this action takes place in the Interphase)

The cell duplicates its DNA to provide two copies.

What are the three stages in the Interphase? What do they mean?

G1, S, G2. “Growth or Gap 1”, “Synthesis”, and “Growth or Gap 2”.

Since cells split in half because of mitosis, how do cells prevent themselves from gettings smaller and smaller?

Before they go through mitosis, they grow, then split.

The cell spends most of its time in the ________

Interphase

What is a centrosome?

It is the place where the spindle fibers are attached to.

What are the four stages of mitosis?

Prophase, Metaphase, Anaphase, Telephase

What are the other 2 supporting phases in Mitosis?

Cytokinesis and the interphase

During which phase ins the DNA duplicated?

During the Interphase

What is chromatin?

Chromatin is DNA that is present in chromosomes and chromatin eventually create new chromosomes in the daughter cells.

In which phase are the chromatids pulled apart?

During the Anaphase

In what phase does a new nuclear envelope develop?

During the telophase, the last phase of Mitosis.

During what phase do the chromosomes line up in the middle of the cell?

In the metaphase

What are the three parts of the cell theory?

1. All organisms are made up of one or more cells

2. The cell is the basic unit of structure and function of any organism

3. All cells come from other cells in existence

All cells have which four qualities in common?

A cell membrane, cytoplasm, genetic material, and ribosomes.

A prokaryote cell has no ___ and has ____ _____ DNA. They lack internal _______

nucleus, free floating, compartments

Most prokaryotes are simple, ____ organisms. They reproduce ______ (binary fission), and their only organelles are ______

unicellular, asexually, ribosomes

What is another name for an internal structure in a cell?

An organelle

Eukaryotes have a true ______ with organized ___

Nucleus, DNA

How do eukaryotes reproduce?

Asexually or sexually

Is a virus considered a living thing or a cell?

No.

All cellls have ____ _____ (or _____ _____)

plasma membranes, or cell membranes.

What are some examples of where the cell membrane is? (Eukaryote)

Around the cell, in the nucleus, vacuoles, mitochondria, and chloroplasts

The plasma membrane makes up what two structures in a cell? (Eukaryote)

The Golgi Apparatus and the endoplasmic reticulum

What is the function of the cell membrane?

To control what comes in and out of the cell, to maintain an internal balance called homeostasis. It also protects and supports the cell

What is selective permeability?

It is the reason that only certain substances based on the solubility, size, and charge are able to pass through

What par of the cell has the phospholipid bilayer? What two parts are contained in it? How do these two parts respond to water?

The phosphate head and the fatty acid tails. The tails are hydrophobic and the heads are hydrophillic. The phospholipid bilayer is in the cell membrane.

The phospholipid bilayer is embedded with _____ and strengthened with _____

proteins, cholesterol

What is the model we relate the phospholipid bilayer to? Why is this?

The fluid mosaic model. The “fluid” represents the proteins that are constantly flowing and moving within the phospholipid bilayer and the “mosaic” is a combination of proteins and carbohydrates within the lipid bilayer

What two functions do proteins serve in the cell membrane?

They act as a transport substance and can be used as enzymes.

What is the function of carbohydrate chains in the cell membrane?

They act as a flag that are recognized by chemicals and molecules from the inside or outside of the cell to prevent getting attacked by the immune system.

Cell transport definition?

It is the movement of substances across the cell membrane

What are the two types of transport?

Active transport and passive transport

What are some qualities that passive transfer represent?

Passive transport does not use energy, molecules move randomly, and molecules move with the concentration gradient—moving from high to low

What are three types of passive transport? What are their concentration gradients?

Diffusion, Facilitated Diffusion, and Osmosis. They all move from an area of high concentration to an area of low concentration (with concentration gradient)

Molecules with no ____ can be transported during diffusion. Until how long does diffusion continue?

Molecules with no charge can be transported during diffusion, and diffusion keeps going until equilibrium is reached, or there is equal concentration of all the molecules. However, the molecules keep moving around but stay spread out

Diffusion has what type of movement in particles?

Random movement

Facilitated diffusion is the diffusion of _____ particles along a high to low gradient with the help of what substance?

Diffusion of specific particles with the help of transport proteins.

Why are transfer proteins called specific?

Because they only let some molecules pass through the cell membrane

What type of molecules cannot pass through when facilitated diffusion is happening?

Large or highly charged molecules

What is osmosis? What is its concentration gradient?

Diffusion of water through a selectively permeable membrane, and it moves from high to low.

Why is water a free passage and exit with no issues through the cell membrane?

Since water is so small and there is so much of it, the cell cannot control how much comes in or out. This means water can affect the size of a cell

What happens in a hypotonic reaction? Where does water move? What is this also called?

A hypotonic reaction is when water enters a cell through the outside. This causes the cell to swell and possible burst. It is also called cytolysis

What happens in a hypertonic reaction? Where does water move? What is another name for this?

A hypertonic reaction is when a cell shrivels up. Water moves from the cell to outside the cell, causing it to lose a lot of its volume, and it is also called plasmolysis

What happens in an isotonic reaction? Where does water flow and what is another name for this?

In an isotonic reaction, water doesn’t move at all because both areas have an equal amount of concentrion. Therefore, the cell stays the same size and it is also called dynamic equilibrium

What is tonicity?

The ability of a solution to alter the volume of cells by changing their water content. It basically determines whether a solution is hypertonic, hypotonic, or isotonic

Solvent vs. solute?

Solute is the chemical that is dissolved in the solvent.

What are some defining characteristics of active transport?

It uses ATP energy, it actively moves molecules to where they are needed, and it moves against the concentration gradient—low to high1

What are the three types of active transport?

Endocytosis, Exocytosis, and protein pumps

What are protein pumps?

They are transport proteins that move molecules from an area of low concentration to high concentration requiring energy

What is endocytosis? What does it form?

Endocytosis is when a cell basically eats something. It takes bulky material inside the cell, and the cell membrane folds around the particle. It forms a food vacuole and digests food. It is also how white blood cells eat bacteria. Uses energy

What is exocytosis?

Exocytosis is when the membrane surrounding material merges with the cell membrane, changing shape. It requires energy, and it forces material out in bulk. It is used by hormones or waste released from the cell.

What do prokaryotic cells use to move around? Since eukaryotic cells do not have this, what does this mean?

Prokaryotic cells use a flagella, or a long tail-like structure. Eukaryotic cells have a hard time moving around because they do not have this.

What four parts of the cell are found in all cells?

DNA, Ribosomes, Cytoplasm, and Cell membrane

Which organelle breaks down and recycles macromolecules?

Lysosomes

If a cell has very high energy requirements, what organelle would have a large quantity?

Mitochondria, because they produce ATP

What does the golgi apparatus do?

It modifies and packages proteins

What organelle is only found in plant cells?

Chloroplasts

What are vesicles and vacuoles used for?

They are used to store or transport materials into and out of the cell

What is the network of protein filaments that support the cell?

It is called the cytoskeleton

What is the role of cholesterol in the cell membrane?

It controls the flexibility of the cell membrane and supports it as well

What are centrioles composed of?

Proteins

What are ribosomes used for?

Protein synthesis

If a plant cell was in a hypotonic reaction, what part of the cell would prevent it from bursting?

The cell wall; it provides stability.I

If a cell was placed in a saline solution, what would happen?

The cell would shrink because salt absorbs water.

What happens during the G1 phase?

The cell grows and organelles are made

What occurs during the S phase?

The DNA is duplicated

What happens in the G2 phase?

The cell double-checks its DNA from the S phase, while preparing for mitosis