Biology Mid Term Review

Biology Mid Term review:

Cancer and Cell:

Cancer Readings- (2) Understanding Cancer article

1.Cancer is a group of more than 100 diseases that develop across time and involve the uncontrolled division of the body’s cells.

- Cancer is a disease in which a single normal body cell undergoes a genetic transformation into a cancer cell. This cell and its descendents, proliferating across many years, produce the population of cells that we recognize as a tumor, and tumors produce the symptoms that an individual experiences as cancer.

2. cancer can develop in virtually any type of the body’s tissues, and each type of cancer has its unique features, the basic processes that produce cancer are quite similar in all forms of the disease.

3. a tumor, or mass of cells, is formed of a rapid division of cells. The tumor can either remain in the tissue it originated from, or it can begin to invade nearby tissues, causing organ failure and tissue damage.

4. an invasive tumor is said to be malignant, and cells shed into the blood or lymph from a malignant tumor are likely to establish new tumors (metastases) throughout the body.

5. one of the most important early observations that people made about cancer was that its incidence varies between different populations. These observations and others suggested that the origin of cancer may lie outside the body and ,more important, that cancer could be linked to identifiable and even preventable causes.

-these ideas led to a widespread search for agents that might cause cancer,

6. another field of study that contributed to scientists’ growing understand of cancer was cell biology.

-cell biologists studied the characteristics of cancer cells, through observations in the laboratory and by inference from their appearance in the whole organism.

7. The key difference between normal cells, however, is that cancer cells have lost the restraints on growth that characterize normal cells.

8. A central feature of today’s molecular view of cancer is that cancer does not develop all at once, but across time, as a long and complex succession of genetic changes. Each change enables precancerous cells to acquire some of the traits that together create the malignant growth of cancer cells.

9. Oncogenes are the mutated forms of proto-oncogenes, and cause the proteins involved in these growth-promoting pathways to be overactive. So in a nutshell, they speed up cell division if it is starting to slow down

10. the role of tumor-suppressor genes (in a nut shell) is to slow down the process of cell division if it starts to divide at a more rapid pace, which could eventually cause tumors/cancer.

11. In addition to the controls of proliferation (oncogenes and tumor-suppressor genes) the body has 3 major “back up systems” that can help the cells avoid runaway cell division…

1. DNA repair system- operates in virtually every cell in the body, detecting and correcting errors in DNA.

2. Apoptosis- prompts a cell to commit suicide if some essential component is damaged or its control system is deregulated.

3. The ability to limit the number of times a cell can divide, and so ensures that cells cannot reproduce endlessly. This system is governed by a counting mechanism that involves DNA segments at the ends of chromosomes, called telomeres, these segments shorten each time a chromosome replicates.

12. the relative risk of receiving cancer compares the risk of developing cancer between persons with certain exposure to characteristics and persons who do not have this exposure or characteristics.

13. the earlier cancer is detected the greatest risk your survival is.

Know stages of mitosis stem cells and clones

Interphase: composed of 3 phases, G1, S phase and G2. It is basically a cell being a cell and it prepares the cell for dividing by producing extra nutrients, organelles and DNA. G1 is right after cell division/cytokinesis, it is cell growth. S phase is right after G1 and this is the stage when the cell replicates it’s DNA, which is composed of 2 sister chromatids. G2 is the preparation for mitosis and is the stage right before the M phase/cell division/mitosis.

Prophase: is the first phase of mitosis and cell division. The centrioles start to go to the other sides of the cell while creating spindle fibers. The nuclear envelope starts to dissolve and chromatins condense into the chromosomes.

Metaphase: The chromosomes line up in the middle of the cell, while the centrioles go to the opposite ends. The spindle fibers attach the each centromere of each chromosome.

Anaphase: The spindle fibers splits the chromosomes, and the chromatids start to go to each side of the cell.

Telophase: The chromosomes gather at each end of the cell with the centrioles. The Nuclear envelope reforms around each set of chromosomes and the cell membrane gets ready to divide.

Cytokinesis: The cytoplasm pinches in half creating 2 new daughter cells.

Stem Cells: stem cells are like blank cells that can become any somatic cell.

Clones: Genetic replications of an organism. All of the DNA is reproduced to make an exact copy.

Know stages of mitosis stem cells and clones

Metaphase: The chromosomes line up in the middle of the cell, while the centrioles go to the opposite ends. The spindle fibers attach the each centromere of each chromosome.

Anaphase: The spindle fibers splits the chromosomes, and the chromatids start to go to each side of the cell.

Telophase: The chromosomes gather at each end of the cell with the centrioles. The Nuclear envelope reforms around each set of chromosomes and the cell membrane gets ready to divide.

Cytokinesis: The cytoplasm pinches in half creating 2 new daughter cells.

Stem Cells: stem cells are like blank cells that can become any somatic cell.

Clones: Genetic replications of an organism. All of the DNA is reproduced to make an exact copy.

Chapter 3 3.1 3.2 3.3

Key terms:

Ecology: the study of ecosystems and the organisms within the ecosystem.

Biosphere: Contains all parts of the planet a.k.a the planet.

Species: A group of very similar organisms that are able to reproduce with each other

Autotroph: A producer, and organism that makes its own food

Producer: an organism that makes its own food using chemosynthesis or photosynthesis

Consumer: An organism that needs to eat other organisms to obtain energy.

Chemosynthesis: The process of making energy through chemical reactions is prevalent in producers and autotrophs.

Herbivore: An organism that needs to consume producers (plants) to gain energy

Carnivore: An organism that needs to consume other consumers to gain energy (meat).

Detritivore: An organism that needs to consume dead matter to gain energy.

Omnivore: An organism that can eat consumers and producers to obtain energy (meat and plants)

Decomposer: An organism that decomposes dead matter and gains energy from the process and releases the molecules back into the environment.

Food Web: Intertwining food chains in an ecosystem.

Trophic Level: A level of a food web, chain, or pyramids.

Energy Pyramid: Shows the amount of energy at each trophic level. Only 10% energy is transferred from each trophic level to the next.

Cycles:

Water: First from the oceans, lakes the water evaporates or transpiration which water is evaporated directly from the leaves of plants. Once in the atmosphere water condenses into water droplets to form clouds in condensation. When the droplets become large enough the precipitate back to earth in the form of water, snow, sleet, or hail in precipitation. Once the water comes back to earth it runs off into the ocean, lakes, and streams. Some water seeps into the soil in seepage and is absorbed by plants in root uptake. The rest flows back into the ocean.

Carbon: Carbon dioxide is released into the atmosphere or ocean through volcanic activity, respiration, deposition, photosynthesis, human activity. It is only taken out through plants or micro organisms that are undergoing photosynthesis or chemosynthesis.

Nitrogen: Nitrogen goes from N2 in the atmosphere into bacterial nitrogen fixation which converts is into NH3 or is has uptake into by producers and reused by consumers and excretion converts it into NH3. Bacterial nitrogen fixation converts it into NO3 and NO2. Denitrification releases N2 into the atmosphere.

Phosphorus: Plants absorb phosphorous from the land and animals consume the plants and gain the phosphorous and through excretion is absorbed back into the land or ocean. And the same cycle occurs in the ocean.

Limiting Nutrient: Is a nutrient that has a limited supply like phosphorous.

Chapter 10 10.2 10.3

Key terms: cell cycle (all phases- look at “cells alive”) , cell cycle checkpoints,

mitosis, cytokinesis, chromatin chromosome cyclins

Know stages of mitosis stem cells and clones

Stages of Mitosis:

1. Prophase- first and longest phase of mitosis.

2. Metaphase- often only last a few minutes

3. Anaphase- ends when chromosomes stop moving

4. Telophase- final phase of mitosis

Stem Cells are unspecialized cells which have the potential to differentiate and become specialized in structure and function, into a large variety of cell types. Early in embryonic development, the stem cells produce every tissue in the body. Research shows that stem cells are also found in adult cells. It is has been found that implants of stem cells can reverse affects of brain injuries in mice. Researchers hope that this is will be possible for humans to reverse brain and spinal cord injuries. By the use of stem cells, we might be able to grow new liver tissue, replace heart valves or even reverse the effect of diabetes.

Clones are exact copies of an organism, its DNA is transferred from the cell of that exact organism to be able to make a copy of that same organism.

Cell Cycle:

1. G1 Phase – Growth and development.

2. S Phase – Synthesis stage – Chromosome replication.

3. G2 Phase – Growth and development.

4. M Phase – Cell Division stage.

Cell Cycle Checkponts:

1. G1 Checkpoint – Checks size and environment.

2. G2 Checkpoint – Checks size, environment, and DNA replication.

3. Metaphase Checkpoint – Checks if chromosomes are aligned on spindle.

Mitosis- the phase of the cell cycle in which the cell divides

Cytokinesis- after the telopase, the process of cytokinesis pinches the cell into two peices

Chromatin- is the clones of chromosomes which are made when preparing for mitosis

Chromosomes- formed the cell is finished dividing and contain the cell DNA

Cyclins- create the proteins necessary for the cell to trigger the checkpoints in the cell cycle

Chapter 8- 9

Chapter 8: Photosynthesis

Section 8-1: Energy and Life

Energy is the ability to do work.
Plants and some other types of organisms are able to uses the sunlight’s energy to produce food.
Autotrophs: organisms that can create their own food.
Heterotrophs: organisms that cannot directly use the sun’s energy to make food. They depend on other organisms for their energy.
Energy can come in many forms, such as light, electricity and heat.
It is also stored in chemical compounds.
Adenosine triphosphate (ATP): a chemical compound that cells use to store and release energy.

Section 8-2: Photosynthesis: An Overview

Photosynthesis: Plants use energy from the sunlight to convert water and carbon dioxide into high-energy carbs (sugars and starches). This process provides glucose for the plant, a requirement to live and respire. This process also creates oxygen as a waste product.
Equation for Photosynthesis: 6CO2 + 6H2O > C6H12O6 + 6O2
Pigments: light-absorbing molecules that plants use to gather the sun’s energy.
Chlorophyll: the main pigment in plants.
Respiration: Respiration is the process of breaking down glucose and other food molecules to create ATP, or useable energy for your body.

Section 8-3: The Reactions of Photosynthesis

Thylakoids: saclike photosynthetic membranes that organize chlorophyll and other pigments.
Photosystems: clusters of chlorophyll and other pigments
There are two different types of photosystem reactions: light-dependent reactions and light-independent reactions(Calvin Cycle)
Stroma: the remaining parts of the chloroplast
A cell uses electron carrier molecules such as NADP+ (a chemical compound), to move sunlight-excited electrons about the cell
When you add and electron to the NADP+ through the electron chain NADPH and is free to carry electrons about the cell
Light dependent reactions : produce oxygen gas, and convert ADP and NADP+ into energy carriers ATP and NADPH
Calvin Cycle: uses ATP and NADPH from the light dependent reaction to produce high energy sugars

Chapter 9: Cellular Respiration

9.1 Chemical Pathways

A calorie is the amount of energy needed to raise the temperature of I gram of water 1 C
Glycolysis: the process in which hone molecule of glucose is broken in half, producing two molecules of pyruvic acid
Cellular respiration is the process that releases energy by breaking down glucose and other food molecules in the presence of oxygen
6O2 + C6H12O6 > 6CO2 + 6H2O + ENERGY = RESPIRATION

Chapter 8- 9

Over view of Photosynthesis and respiration

Photosynthesis is the process in which a plant takes in sun light and uses it to make Glucose. In respiration the glucose converts into ATP which the cell can use for energy

Chemical equations relationship between photosynthesis and respiration

Photosynthesis

6H2O + 6CO2 ------> C6H12O6+ 6O2

Respiration

C6H12O6 + 6O2 --> 6CO2 + 6H2O + energy

How do each relate to the carbon cycle and energy pyramid

The role of photosynthesis and respiration is related to the carbon cycle because when a plant makes glucose it lets of oxygen back into the air. When the plants die it will get eaten by the bacteria in the dirt. Or over millions of years it will turn into fossil fuel.

Role of mitochondria and chloroplast

Chloroplast is used to take sunlight and convert it to glucose. The glucose then goes to the mitochondria to be converted into ATP for energy.

Role of sunlight, carbon dioxide, glucose, oxygen, water, and ATP

Sunlight is the primary energy source that is used b the chloroplast, the glucose is needed by the plant for food and to be converted into ATP, which is energy for the plant. Oxygen is used for undergoing photosynthesis, and carbon dioxide, which is a byproduct of photosynthesis, is used in respiration, which is the opposite of photosynthesis as a equation.

Microscope- parts and how it works

Arm- connects all components

Base-holds everything

Course adjustment- brings lens to focus

Diaphragm- regulates light amount

Eyepiece- where you look through to see

Fine adjustment- to bring lens into a higher focus

High-power objective- yellow

Lamp- where the light bulb is

Low-power objective- red

Mirror- reflects the light

Nosepiece- holds the four different lenses

Stage- where the slide goes

Stage clip- where the slide is held in place

Stage opening- where light shines through

Similarities and differences between prokaryotic and eukaryotic cells

Similarities: Both are cells.

Differences: Eukaryotic cells are bigger than prokaryotic in size. Prokaryoticcells don’t have a nucleus and eukaryotic cells do.

Structure and Function of organelles

Nucleus-controls most of the cells processes and contains DNA

Mitochondrion- uses energy from food to make high-energy compounds

Cell wall- provides support and protection for the cell

Cytoskeleton- maintains cell shape with network of protein filaments

Chloroplasts- uses energy from sunlight to make food molecules

Endoplasm reticulum- where lipid components of the cell membrane are assembled and where proteins are chemically modified

Golgi apparatus- packages proteins and other materials from the ER

Cell membrane- thin, double layered sheet around the cell

Cell- the basic unit of life

Organelle- specialized structures within a cell that perform important cell functions

Cell membrane- Is an organelle that is made up of phosopolipid heads

lipids- Phospolipids heads arehydrophilic which means they like water, the tails are hydrophobic and they line up together to make a water tight barrier.

proteins- There are three types of proteins, Receptor proteins which let the right shaped molecules into the cell, glycoproteins which recognize molecules and let them in accordingly, and channel proteins which allow molecules in to be shaped and them let them into the cell.

cholesterol- attaches to the phospholiped tails to strengthen them.

Movement across-

transport

active vs passive- Passive transport is the basic mode of diffusion, in active transport, the molecules move from low to high concentration by using atp formed by the mitochondria during respiration.

diffusion- Aprocess when the molecules tend to move from an area where they are more concentrated to an area where they are less concentrated.

facilitated diffusion- The movement of specific molecules which are across the cell membranes through protein channels.

Active transport- as powerful as diffusion Is cells sometimes must move materials in the opposite direction, against a concentration difference.

proteins: channel pore surface (recognition and attachment)