Biology// Ch. 3//STUDY Guide

Explain an example of negative feedback

"After eating a meal, your blood glucose level increases. Islet cells in your pancreas detect the rise in blood sugar, and release insulin into the bloodstream. Insulin binds to receptors on cells throughout the body, allowing the cells to take up glucose from the blood. This lowers blood glucose levels back to a normal level." This is negative feedback because it needs to lower blood glucose levels back to abnormal level.

Explain an example of positive feedback

"During childbirth, the fetus is pushed against the uterine opening, causing it to stretch. Receptors that detect the stretching send signals to the brain. The brain sends both neural and hormonal signals which increase both the contraction force and the contraction frequency in the smooth muscles of the uterus." This is positive feedback because this is something that much continue and move forward in order for the baby to be delivered.

Use one example of negative feedback to list the organs and organ systems involved in maintaining homeostasis

"When a person has not taken in sufficient water they become dehydrated. This may cause a loss of blood pressure, which will trigger the release of antidiuretic hormone(ADH) from the hypothalamus and pituitary glands. This hormone signals the kidney to allow reabsorption or water by the blood vessels to bring the blood pressure back to normal conditions." The kidney, blood vessels, hypothalamus, and pituitary glands.

Draw and label a diagram of a nerve cell

*IN STUDY GUIDE AND 3-6 NOTES*

Describe the cell cycle in eukaryotes

-The eukaryotic cel cycle consist of four phases: G1,S,G2, and M -the length of each phase and the cycle as a whole depends on the type of cell -together the G1,S, and G2 phases are interphase -the G in G1 and G2 stand for gap even though these phases are actually periods of intense growth

Vacuole

-cellular organelles that store materials like water, salts, proteins and carbohydrates -many cells have a large central vacuole filled with liquid -this central vacuole increases the rigidity of the cells making it possible for plants to support heavy structure

Microtubules (include flagella and cilia)

-hollow structures made up of proteins known as tubulins -help maintain cell shape -important in cell division, where they form a structure known as the mitotic spindle, which helps to separate chromosomes -in animal cells, structure known as centrioles are formed from tubulins •centrioles are located near the nucleus and help to organize cell division •centrioles are not found in plant cells -microtubules help to build projections from the cell surface, which are known as cilia and flagella, that enable cells to swim rapidly through liquids •small cross-bridges between the microtubules in these organelles use chemical energy to pull in, or slide along, the microtubules, allowing cells to produce controlled movements

Golgi apparatus

-it modifies, sorts, and packages proteins and other materials from the ER for storage in the cell or release outside the cell -proteins produced in the rough ER move next into the Golgi apparatus, which appears as a stack of flattened membranes -the proteins are bundled into tiny vesicles that bud from the ER and carry them to the Golgi apparatus

Mitochondria

-power plants of the cell -they convert the chemical energy stored in food into compounds that are more convenient for the cell to use -in humans, all or nearly all of our mitochondria come from the cytoplasm of the ovum, or egg cell(all mitochondria from mom)

Cell membrane

-regulates what enters and leaves the cell and also protects and supports the cell -the composition of nearly all cell membranes is a double-layered sheet called a lipid bilayer, which gives cell membranes a flexible structure and forms a strong barrier between the cell and its surroundings

Lysosomes

-small organelles that are filled with enzymes -the enzyme contained in lysosomes break down lipids, carbohydrates, and proteins into small molecules -lysosomes also break down organelles that have outlived their usefulness

Ribosomes

-small particles of RNA and protein found throughout the cytoplasm in all cells that produce proteins by following coded instructions that come from DNA -each ribosome is like a small machine in a factory, turning out proteins on orders that come from its DNA, "boss"

Chloroplasts

-the biological equivalents of solar power plants. They capture the energy from sunlight and convert it into food that contains chemical energy in a process called photosynthesis

Describe Anaphase (3rd)

-the centromeres are pulled apart and the chromatids separate to become individual chromosomes -the chromosomes separate into two groups near the poles of the spindle

Describe Metaphase (2nd)

-the centromeres of the duplicated chromosomes line up across the center of the cell -the spindle fibers connect the centromere of each chromosome to the two poles of the spindle

Describe Telophase (4th)

-the chromosomes spread out into a tangle of chromatin -a nuclear envelope re-forms around each cluster of chromosomes -the spindle breaks apart, and a nucleolus becomes visible in each daughter nucleus

Describe the prokaryotes in cell cycle

-the cycle can take place very rapidly under ideal conditions -prokaryotic cells divide when they reach a certain size -the process of cell division in prokaryotes is known as binary fission. This process results in the production of two genetically identical daughter cells

Describe Prophase (1st)

-the duplicated chromosome condenses and becomes visible -the centrioles move to opposite sides of nucleus and help organize the spindle -the spindle forms and DNA strands attach at a point called their centromere -the nucleolus disappears and nuclear envelope breaks down

Cell wall

-the main function of the cell wall is to provide support and protection for the cell -prokaryotes, plants, algae, fungi, and many prokaryotes have cell walls -animal cells do not have cell walls -cell walls lie outside the cell membrane and most are porous enough to allow water, oxygen, carbon dioxide, and certain other substances to pass through easily

Cytoskeleton

-the network of protein filaments in a eukaryotic cell that gives the cell its shape and internal organization and is involved in movement Separate card: -microfilaments -microtubules -cilia -flagella

Nucleus

-the nucleus is surrounded by a nuclear envelope composed of two membranes -pores in the membranes, called nuclear pores, allow material to move in and out of the nucleus -chromosomes are found in the nucleus. Most of the time chromosomes are spread out into chromatin -within the nucleus there is a small dense region called the nucleolus, which is where the assembly of ribosomes begins

Smooth ER

-the other portion of the ER is known as the smooth ER because ribosomes are not found on its surface -in many cells, the smooth ER contains collections of enzymes that preform specialized tasks, including the synthesis of membrane lipids and the detoxification of drugs

Rough ER

-the portion of the ER involved in the synthesis of proteins •it is giving this name because of the ribosomes found on its surface •newly made proteins leave these ribosomes and are inserted in the rough ER, where they may be chemically modified

Cytoplasm

-the portion of the cell outside the nucleus -the majority of the cells organelles are located in the cytoplasm

Microfilaments

-threadlike structures made of a protein called actin -the frameworks of microfilaments support the cell -help the cell to move -their assembly and disassembly is responsable for the cytoplasmic movements that allow cells, such as amoebas, to crawl along surfaces

Endoplasmic Reticulum

-where lipid components of the cell membrane are assembled, along with portions and other materials that are exported from the cell -eukaryotic cells contain and internal membrane system known as the ER

Pluripotent cell

A cell that can develop into most, but not all types of cells. After the first few rounds of cell division occur, these early cells become pluripotent.

Totipotent cell

A cell that is completely undifferentiated, that is, it is capable of becoming any type of cell. The cells produced by the 1st few rounds of cell division are totipotent.

Response

Action of and organism as a result of stimulus

Multi potent cell

Adult stem cells are multi potent, that it, they have a limited ability to differentiate into different types of cells

Explain how/when cell differentiation occurs

After fertilization occurs, the developing organism progresses through a series of developmental stages. During the development of an organism, cells differentiate into many different types of cells. The process of differentiation determines a cells ultimate identity and function within the body. Cell differentiation is controlled by a number of different factors, many of which are not fully understood. Once cell differentiation is complete, cells cannot become other types of cells.

Receptor

Cells have receptors onto which signaling molecules can bind. Receptors must recognize stimulus. The changes are detected by the receptor.

Tissue

Cells make up tissues. A tissue is a group of similar cells that performs a particular function.

Explain what happens to the cell cycle during cancer

During cancer things may be stopped in the cell cycle an things may be inserted or deleted. There are check points throughout the cell to check that everything is going as planned and cancer bypasses them. Cancer is also due to damaged DNA.

Describe the two types of stem cells

Embryonic stem cells are pluripotent, meaning they are capable of differentiating into nearly any time of body cell. Adult stem cells are multi-potent, meaning they have a limited ability to differentiate into different types of cells. Normally, the stem cells of a particular organ or tissue can only differentiate to produce cells of that tissue type. *Ex. In 3-4 Notes*

Lists the stages of the cell cycle and describe what occurs in each stage

G1 phase - cells do most of their growing during this phase. During this phase cells increase in size, synthesize proteins and organelles S phase - during this phase DNA is replicated. The S stands for synthesis. At the end of this phase the cell contains twice as much DNA G2 phase - during this phase the cell prepares the molecules and organelles needed for cell division. This is usually the shortest of the interphase phases M phase - during this phase the cell divides into 2 identical daughter cells. This phase is separated into 2 stages: stage 1=mitosis stage 2=cytokinesis

Permeability

If a substance is able to cross a membrane, the membrane is said to be permeable to it. If it cannot pass across it, then it is impermeable.

Cytokinesis

It involves the division of the cytoplasm and the separation of the two daughter cells. It completes the process of cell division, and the cell splits from once cell into 2. In animal cells the cell membrane draws together and is pinched into 2 nearly equal parts. In plant cells a cell plate forms between the 2 daughter cells, this becomes the cell membrane. Then the cell wall forms.

Mitosis

It involves the division of the nucleus and chromosomes. It has 4 phrases: prophase, metaphase, anaphase, telophase. It is also stage 1 of the M phase

feedback inhibition

It is the same as negative feedback. It is a buildup of the end product of the systems that shuts the system off.

Negative feedback

Most homeostatic control systems function by negative feedback. In negative feedback a buildup of the end product of the system shuts the system off.

List and describe the functions of mitosis in multicellular organisms

Multicellular organisms depend on mitosis for growth and repair. When a multicellular organism grows it makes more cells through mitosis. Organism can repair some of their tissues, using mitosis to generate new cells

Describe G0 phase of the cell cycle and when cells enter this phase

Occasionally cells stop dividing and enter the G0 phase. The factors may determine whether a cell enters G0 is, its stage of development, the type of cell, the resources available. Cells are allowed to leave G0 phase.

Organ system

Organs make up organ systems. An organ system is a group of organs that work together to carryout complex functions.

List the phases of mitosis

Prophase Metaphase Anaphase Telophase

Meiosis

Sexually-reproducing organisms have a 2nd form of cell division that produces reproductive cells with half the number of chromosomes. This is called meiosis.

Vesicles

Smaller membrane enclosed structures that store and move materials between organelles

Positive feedback

Some homeostatic control systems function by positive feedback. In positive feedback, a change in some variable that triggers mechanisms that amplify the change.

Stimulus

Something in the environment that causes a change(can be internal or external)

Cell

The basic unit of structure and function in living things The cells in multicellular organisms are not capable of surviving on their own. They require the "service" of other cells in order to survive. The cells of multicellular organisms become specialized for particular tasks and communicate with one another to maintain homeostasis. The specialized cells in multicelular organisms are organized into different levels.

Effector

The effector organ receives messages and conducts the actual response

Homeostasis

The existence and maintenance of a relatively constant environment within the body

Describe what occurs in meiosis 1

The pairs of homologous chromosomes are separated from each other. PROPHASE 1 - the homologous chromosomes line up together; a process that only happens in meiosis can occur, this is called crossing over(the exchange of DNA between homologous chromosomes, this forms new combinations of alleles on the resulting chromosomes) METAPHASE 1 - the homologous chromosomes line up in their pairs in the middle of the cell. The chromosomes from the mother or from the father can attach to either side of the spindle at random. ANAPHASE 1 - the homologous chromosomes are separated as the spindle shortens and begins to move to opposite sides of the cell TELOPHASE 1 - the spindle fiber dissolves, but a new nuclear envelope doesn't form

Describe what occurs in Meiosis II

The sister chromatids are separated, and the gametes are generated. It results in four genetically unique haploid cells. PROPHASE II - the chromosomes condense METAPHASE II - the chromosomes line up one on top of each other along the middle of the cell; the spindle is attached to the centromere of each chromosome ANAPHASE II - the sister chromatids separate as the spindle shortens and move to opposite ends of the cell TELOPHASE II - the nuclear envelope forms around the chromosomes in all four cells, this is followed by cytokinesis. After cytokinesis, each cell had divided again. Therefore, meiosis results in 4 haploid, genetically unique daughter cells, eacb w half the DNA of the parent cell. In human cells, the parent cell has 46 chromosomes, so the cells produced by meiosis have 23 chromosomes(these cells will become gametes)

Homologous chromosomes

They are chromosomes that contain the same genes, although each chromosome in the homologous pair may have different alleles

Organelle

They are specialized structures that preform important cellular functions within the cell. The majority of the cell organelles are located in the cytoplasm.

Organ

Tissues make up organs. An organ is a group of tissues that work together to carryout complex functions.

Sister chromatids

Two sister chromatids make up a single replicated chromosome

***DRAW A SAMPLE HISTOGRAM****

USE ONE OF THE DATA SETS FROM THE NOTE

cell differentiation

the process by which a cell becomes specialized for a specific structure or function; there is no cell differentiation in unicellular organisms, but there is in multicellular.

Cell cycle

the series of events in which a cell grows, prepared for division and divides to form two daughter cells

Describe the fluid mosaic model of the cell membrane

°most cell membranes contain protein molecules that are embedded in the lipid bilayer -carbohydrate molecules are attached to many of these proteins -because the proteins embedded in the lipid bilayer can move around and "float" among the lipids, and because so many different kinds of molecules makeup the cell membrane, scientists describe the cell membrane as a "fluid mosaic" -some of the proteins form channels and pumps that help to move material across the cell membrane -many of the carbohydrate molecules act like chemical identification cards, allowing individual cells to identify one another

Explain how nerves send and receive signals

•Neurons pass messages to each other using as special type of electrical signal -these signals bring information to the brain from outside of your body, such as the things you see, hear, and smell, or instructions for your organs, glands and muscles •neurons receive signals from neighbor neurons through their dendrites -the signal travels to the main cell body, aka the soma -next, the signal leaves the soma and travels down the axon -as a final step, the signal leaves through the synapse to be passed along to the next neuron