Download Chapter 3 – Cell Structure and Function

Midterm Review Packet
Living Environment, Chapters 1, 2, 7-15
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Chapter 1 Science of Biology
Organism: an individual living thing
Biology: The study of living things
The Scientific Method
- State problem or question, what do you want to know?
- Research information already known about the topic
- Propose a hypothesis (educated guess/ possible explanation)
- Test hypothesis / Experiment
Experimental/Variable Group: changing something, varying
Control Group: No change, used for comparison
- Analyze findings make conclusions
- Repeat experiment for reliability
When testing consistently supports hypothesis it becomes accepted as valid
(true) – Theory, a logical explanation (ex: Cell Theory)
- Independent Variable: variable I change
- Dependent Variable: is dependent on the Independent variable
o Ex: Protein drinks and strength –
 Independent variable: number of protein drinks
 Dependent variable: number of pushups I can do
Lab Skills: Microscope
- Parts of a microscope
- 10x – Eyepiece, Low Power – 10x, High Power – 43x
- Total magnification is Eyepiece x Power
o Low Power magnification is 10 x 10 = 100 times the image
o High Power magnification is 10 x 43 = 430 times the image
- Image always appears to move opposite the direction you are moving
it. Image is upside down and reversed.
- Never use coarse adjustment in High Power, can break slide
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CH 1 Necessary Life Processes Nutrition: able to take in material from which energy can be made
Transport/ Circulation: able to move material around the cell/body
Excretion: able to eliminate waste
Regulation: able to control the reactions occurring w/in body and cell
Reproduction: able to reproduce another cell or organism
Respiration: able to create energy (ATP)
Synthesis: able to produce larger molecules from smaller building blocks
Growth: able to become larger/more complex/more experienced
Homeostasis: maintain a stable internal environment
Metabolism: all of the chemical processes occurring within cells of organism
Chapter 2 – Chemistry of Life
H2O is a polar molecule – has a positive charged end and a negative end.
H2O
H+ and OH- (hydrogen and hydroxide ions) NEUTRAL
When you put an acid in water it gives off H+ (hydrogen ions) HCl
When you put a base in water it gives off OH- (hydroxide ions) NaOH
H+ + ClNa+ + OH-
pH scale: measures strength of acids and bases (water = 7 = neutral)
pH of 0-6 is acid
pH of 7 is neutral / water
Acids are stronger the lower the number
pH of 8-14 is base
Bases are stronger the higher the #
Organic Compounds: CONTAIN at least 2 CARBON!! (& usually H) Ex: C6H12O6
Inorganic Compounds: DO NOT contain carbon. Ex: H2O
4 Organic Macromolecules (have 2 or more Carbon)
1. carbohydrates
2. lipids
3. proteins
4. nucleic acids
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1. Carbohydrates: sugars and starches, have C, H, O
Monosaccharides (one sugar by itself) Ex: glucose, galactose, fructose
Disaccharides (2 sugars joined together) Ex: sucrose = glucose + fructose
Polysaccharide (many sugars ) – Starch, glycogen
---------------------------------------------------------------------------------------------------2. Lipids: waxy, fatty, oils, cholesterol. Made of 3 fatty acids and 1 glycerol.
3 fatty acid tails
3. Proteins: made of amino acids bonded together by peptide bonds. C, H, O, N
Building blocks of cells.
- ENZYMES ARE PROTEINS !!
- PROTEINS HAVE (N) – NITROGEN!
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Enzymes are special proteins
Enzymes are catalysts: change the rate of reactions (speed them up). “ase”
Ex: RNA Polymerase enzyme speeds up process of making RNA
4. Nucleic Acids: DNA and RNA
Made of nucleotides (phosphate, nitrogenous base, and sugar)
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Chapter 7 – Cell Structure and Function
THE CELL THEORY:
1. All living things are made of cells
2. Cells are the fundamental unit of function
3. All cells come from cell division of pre-existing cells
MICROSCOPES
Compound Light Microscope : allows LIGHT to pass thru specimen
- 18th/19th Century Light microscopes lead to discover of the Cell Theory
Electron Microscope: uses a beam of ELECTRONS instead of light
Can magnify up to 1000 times larger than a light microscope. Modern microscope.
CELL STRUCTURE
Cell Membrane:
- Protects and regulates what goes in and out of cell.
- Phospholipid Bilayer: cell membrane is made of 2 layers of LIPIDS &
PROTEINS
Cell Wall: ONLY FOUND IN PLANTS !!!!!!!!!!!!!
- Cell wall is extra protection and support of plant cells in addition to membrane
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How do substances get across the cell membranes?
Passive Transport:
Substances pass through cell membrane WITHOUT using energy.
Diffusion: DOES NOT NEED ENERGY. Substances move HIGH TO LOW
(substances will move right to left – high to low)
Facilitated Diffusion : NO ENERGY, but PROTEINS help substances across
membrane
Osmosis - diffusion of water through a membrane
---------------------------------------------------------------------------------------------------Active Transport – REQUIRES ENERGY because moving LOW TO HIGH
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Inside the Cell
Nucleus: control center in center of cell. Where DNA genetic info is kept.
EUKARYOTES : have a nucleus.
PROKARYOTES: do not have a nucleus.
Cytoplasm: fluid/jelly inside the cell
Endoplasmic Reticulum: Network of channels extending from the nucleus into the
cell. Transports materials.
Rough ER: have RIBOSOMES - SITE OF PROTEIN SYNTHESIS
- Smooth ER: Do NOT have ribosomes
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Golgi Apparatus: after proteins made in ER, travel to golgi for packaging
Lysosomes: Clean-up crew, break down and digest substances
Vacuoles: Store materials (water, carbs, proteins, etc)
Centrioles: ONLY IN ANIMAL CELLS. Help with cell division – spindle fibers
Mitochondria: power-house of cells, place where aerobic respiration takes places –
creating energy. Has its own DNA, and double membrane.
Chloroplasts: ONLY FOUND IN PLANT CELLS. Photosynthesis takes place
here. Has its own DNA, and double membrane.
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CH 8 & 9
Photosynthesis and Respiration
Autotroph: Makes it’s own food. Plants, some bacteria
Heterotroph: Cannot make food, eats other organisms. Humans.
Sun’s energy
Photosynthesis (sun’s energy put into bonds of glucose)
Respiration (breaks down glucose releases that energy from bonds and stores it in ATP
energy for cells to use)
ATP : Adenosine triphosphate. Stores energy in 3 phosphate bonds
Photosynthesis: Process of making glucose (sugar) in plants
- Occurs in the CHLOROPLAST.
- Chlorophyll in thylakoid of chloroplast traps sunlight.
6H2O + 6CO2 + Energy from Sun
Glucose (C6H12O6) + 6O2
(Glucose (C6H12O6)
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Respiration: Process of breaking down glucose to release energy (ATP)
- Occurs in the MITOCHONDRIA
- 2 Types of Respiration:
o Aerobic Respiration – OXYGEN PRESENT
o Anaerobic Respiration (Fermentation) – NO OXYGEN
AEROBIC RESPIRATION: Oxygen present
Glucose (C6H12O6) + 6O2
6H2O + 6CO2+ 34 ATP (Energy)
ANAEROBIC RESPIRATION – FERMENTATION: NO OXYGEN
Lactic Acid Fermentation – Occurs during vigorous exercise
Glucose (C6H12O6)
Lactic Acid + some ATP, CO2, H2O
Alcoholic Fermentation – Occurs only in yeasts!
Glucose (C6H12O6)
Alcohol + CO2 + some ATP, H2O
Humans do anaerobic respiration when oxygen is low, producing small amounts of ATP
for a quick energy source until we take in more oxygen and go back to aerobic
respiration for greater ATP.
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Chapter 10 – Cell Growth & Division
CELL CYCLE: time from beginning of one cell division to the next cell division
G1 Phase – most of cell growth & activity
S Phase – chromosome replicate, DNA synthesis
G2 Phase – final preparations before it divides
M Phase – cell division through Mitosis
Interphase: occurs between cell divisions, (G1, S, and G2 phases)
Chromosomes are not visible bc they are in long strands of chromatin
Mitosis: CELL DIVISION - Cell divides into 2 identical daughter cells
o 4 phases: prophase, metaphase, anaphase, and telophase
1. Prophase
-Nucleus starts to disappear, chromatin coils up into chromosomes,
Chromosomes have 2 identical strands called chromatids held together
by centromere. Centrioles get spindles ready.
2. Metaphase
Chromosomes line up in middle of cell
3. Anaphase
Centromere splits, chromatids separate and move to opposite poles
4. Telophase
Cell becomes 2 separate but identical cells. Nuclear membrane forms
around each cluster of chromosomes. Centrioles break down spindles.
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Cytokinesis = cytoplasm divides so each daughter cell has cytoplasm.
CELL PLATE: Only in plants! becomes cell wall
Cell Specialization & Organization
We started as a single cell. That cell went thru millions of mitotic cell divisions.
Cell specialization: specific cells carry out specific functions, specific jobs
Ex: Macrophages- cells that protect, WBCs in blood attack invaders.
Levels of cell organization from least complex to most complex:
CELLS – TISSUES – ORGANS – ORGAN SYSTEM – ORGANISM
Cancer: Cancer cells do not respond to signals to stop growing, so they grow
out of control. Defect in cell cycle regulation.
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Chapter 11 – 15 Genetics
Heredity: characteristics a living thing receives from its parents
Gregor Mendel experimented with pea plants to learn about genes.
Genes: units that determine traits (hair color, height, etc)
Alleles: Different forms of the same gene (hair can be curly or straight)
Dominant allele: when you have both alleles, only one is expressed - the
dominant allele will overshadow the recessive. Dominant alleles are written
with a capital letter, Ex: black fur = B
Recessive allele: is not expressed if a dominant is present, but it can show up
in later generations if 2 recessive alleles are present.
Recessive allele is lowercase letter, Ex: brown fur = b
Homozygous: alleles are the same for the trait (BB or bb)
Heterozygous: pair of alleles are different (Bb)
GENOTYPE: Genetic composition (Ex: heterozygous for trait Bb)
PHENOTYPE: What the genetic composition looks like (bear is black)
Segregation: The 2 alleles separate when sex cells are produced, only 1 copy
passed on by each parent to offspring.
Independent Assortment: when alleles for different traits segregate
(separate) independently. Thousands of traits each with 2 alleles that
randomly separate before passed on to offspring. That’s why one family can
have children with many different traits (hair, eye color) bc they separate
independly.
Segregation and Independent assortment creates lots of genetic variety.
It is the reason you and your siblings don’t look exactly alike. You have
different mixing and matching of alleles from both parents.
Punnett Squares: If B= black fur, b= brown fur. A heterozygous black bear
crossed with a homozygous brown bear would have what genotypes and
phenotypes of offspring?
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Meisosis
Chromosome: DNA tightly coiled around proteins called histones
Most human cells have 46 chromosomes (23 pairs of chromosomes)
1 set of 23 chromosomes inherited from Mom, 1 set of 23 from Dad
Karyotype: (above pictures) photographs of each chromosome
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Diploid: cells that have 2 copies/sets of chromosomes; 46 chromosomes total
All body cells are diploid (skin cells, liver cells, heart cells, etc)
Haploid: Only 1 set of chromosomes – 23 chromosomes total (Half)
Gametes: all sex cells (egg cell, sperm cell, pollen) are Haploid – 23 chromosomes
Meiosis: process of producing gametes that are haploid
- Need to go from diploid (2n=46) to haploid (1n=23)
- Haploid cell will then unite with another haploid sex cell during fertilization
producing embryo cells that are diploid (46 chromosomes)
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2 Stages of Meiosis
Chromosomes replicate, homologous pairs line up & then separate in first division
then those 2 cells divide into 2 more cells each having half the number of chromosomes
at the start of meiosis.
Produces 4 haploid cells. In men = 4 sperm cells, women = 1 egg, 3 polar bodies
Linked genes: genes on same chromosome, inherit together. Freckles & red hair
Crossing-over: when a piece of one chromosome changes places with another
homologous chromosome. Creates even more genetic possibilities.
Gamete formation is random and independent, 50% chance of getting a gene allele
Incomplete Dominance: The heterozygous phenotype is somewhere in between the 2
homozygous phenotype. Red flower x White flower = a pink flower (RW)
Codominance: both alleles affect phenotype. Both alleles are expressed.
Ex: cow with both areas of spots and areas without spots
Multiple Alleles: more than just 2 alleles. Ex: 4 blood types –A, B, O, AB
Polygenic Traits: traits controlled by more than one gene. Ex: shape of your mouth is
not determined by just 1 gene, it is determined by more than one gene
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Discovering DNA
DNA Structure
- Nucleic acid (1 of the 4 organic macromolecules)
Made of nucleotides: phosphate group, nitrogenous base, and a sugar
Watson & Crick: called DNA structure a double helix
HYDROGEN BONDS Between the nitrogenous base pairs:
Adenine bonds with Thymine (A-T). Guanine bonds with Cytosine (G-C)
DNA Replication
DNA replicates during S phase (Synthesis phase). Enzymes separate the 2
strands of DNA and then synthesize 2 new strands that pair with original.
DNA and Chromosomes
Chromosomes are made of chromatin wrapped around histone protein.
Genes are sections of DNA found on a chromosome. Most genes are merely
instructions for protein synthesis. These proteins determine genetic
traits. DNA is a giant code for making proteins.
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RNA
- The sequence of nucleotides in DNA creates a code for building proteins.
- RNA carries out these instructions, reads the code and puts the amino acids
together to make the proteins. Those proteins become traits (hair, eyes, bones)
RNA is a nucleic acid like DNA but it is different:
- the sugar in RNA is ribose, in DNA it is deoxyribose
- RNA is usually single-stranded, DNA is double
- RNA has Uracil instead of Thymine. Uracil binds with Adenine (U-A),
Transcription: process of making mRNA. RNA is basically a copy of DNA,
and this copy is used to make proteins that DNA codes for.
RNA Polymerase: enzyme that binds to DNA and makes mRNA.
mRNA (messenger RNA) carries code from nucleus down to ribosomes on
the Rough ER.
rRNA (ribosomal RNA) is the site where the proteins are actually made
tRNA (transfer RNA) – reads the mRNA code and carries amino acids over
to rRNA where the protein is assembled.
Translation: translating the DNA code into amino acids for proteins.
CODON: 3 bases = 1 amino acid. These amino acids bond to form protein.
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Genetic Mutations
Mutations “change”, mistake in DNA
- A mutation is an inheritable change in genetic information.
Before cell divides it replicates (copies) its DNA. Mutations happen if a
mistake occurs during replication, the DNA does not copy correctly.
Chromosomal Mutation: change in number or structure of chromosomes.
Ex: Down Syndrome (extra chromosome 21), Turners Syndrome (missing X);
Caused by Non-disjunction – homologous chromosomes failed to separate
during meiosis, therefore a sperm or egg either received extra copies of
chromosomes or missing chromosomes.
Polyploidy – 3 or more sets of chromosomes
Gene Mutation: a change that affects only an individual gene
Point Mutation – one incorrect nucleotide base
Frameshift Mutation – insertion or deletion of a nucleotide base. Throws off
reading of codons (groups of 3). Can cause large changes. If the sequence of
bases change, the amino acids could change, and this can change the protein
and its trait.
What can cause mutations?
Exposure to X-rays, Ultraviolet light, certain chemicals, random chance
Only mutations found in the DNA of gametes will pass on to offspring
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The Human Genetic System
Morgan: studied genetics of fruit flies. Easier than humans, they have only
8 chromosomes, reproduce quickly, see traits in generations faster.
Humans: 46 chromosomes (2 sets: 23 from Mom, 23 from Dad)
- Chromosome pairs are numbered 1-23, largest to smallest
- 22 pairs of homologous chromosomes (similar shape/size)
Autosomes: first 22 pairs (NOT the sex chromosomes)
Sex chromosomes: last pair of chromosomes, X Y (male) or XX (female)
Have 50% chance of getting XY, 50% chance of XX
Pedigree: diagram showing inheritance of a trait through generations
Sex-linked Trait: a trait carried on the X sex chromosome. Males only get one
X, if that X has the trait it will be expressed. If a female inherits one X with trait
she is a carrier; if she gets 2 Xs with trait it will be expressed.
Ex: Color-blindness – normal color vision is dominant, if recessive gene is
expressed the person can’t see certain colors properly. The gene is found on the
X chromosome and is 10x more common in males.
Ex: Hemophilia: blood clotting disorder, carried on the X chromosome
Ex: Duchenne Muscular Dystropy: Genetic disorder that causes muscle
weakness because of a defective protein, carried on X chromosome. Looking for
cure – insert a dominant allele into muscle cells
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Genetic Disorders found on autosomes (chromosomes 1-22)
Cystic Fibrosis: defective protein in cell membrane – thick mucus clogs
Tay-Sachs Disease: more common in Jewish families. Rapid breakdown of
nervous system.
PKU – phenylketonuria. Causes mental retardation. Special diet helps.
Huntington Disease: Rare disorder carried by a dominant allele on
chromosome 4. No symptoms till age 30-40, start lose control of muscles.
Sickle-cell Anemia: RBCs shaped like sickle/crescent, affects oxygen use
Disorders due to abnormal pairing of chromosomes
Non-disjunction: chromosome pairs do not separate correctly, extra or
missing chromosomes.
- Klinefelter Syndrome: Males with extra X chromosome. XXY.
Causes mental retardation, sterility, small testes and breast
development.
- Down Syndrome: Extra copy of chromosome 21 – trisomy – 3
chromsomes. Causes mental retardation
- Turner Syndrome: chromosomes don’t separate in meiosis. Sperm
or egg produced without sex chromosome. Zygote is XO.
Chromosome Deletions: pieces of chromosome break off in meiosis.
Chromosome translocation: pieces of chromosome break off and reattach
elsewhere on non-homologues chromosome. Affects vary.
Prenatal Diagnosis: test for genetic disorders before baby is born. Amniotic
fluid containing baby’s cells removed with needle, DNA in baby’s cells tested for
disorders like Down Syndrome, Tay-Sachs, Huntington Disease, etc
Ethical issues involved in having knowledge of disorders
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Genetic Engineering
Selective Breeding: organisms with desired traits are selected and bred
Hybridization: a cross between two different individuals (labradoodle)
Inbreeding: breeding closely related individuals to maintain traits. Risks
bringing together 2 recessive alleles for a genetic defect.
Cloning: producing a genetically identical organism just from a few cells.
Manipulating DNA
Editing DNA – cut, transplant, rewrite, and/or splice together DNA
Cutting tool: restriction enzymes cut DNA at specific nucleotide bases.
Separating tool: Electrophoresis – DNA fragments placed in a gel and will
separate in gel based on size. Use for identifying individuals in court.
Splicing tool: restriction enzymes cut DNA at certain places and leave bases
exposed. These pieces of DNA can then be joined together (spliced)
Recombinant DNA: combining DNA from two different sources
Cell Transformation: putting recombinant DNA into a live cell. This will
change the cell’s original DNA by adding new DNA to it.
Plasmids: small circular pieces of DNA in bacteria and yeast. Scientists attach
pieces of DNA to plasmids to carry new DNA into cells.
Also, needle injected DNA into cells.
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Genetic Engineering: cutting and splicing of genes and DNA from different
sources. Insert new genes into almost any organism, including humans.
Transgenic: organisms transformed with genes from other organisms.
Transgenic bacteria engineered to produce insulin (a human protein). The
insulin is for diabetics who can’t produce enough insulin.
Human Gene Therapy
Cystic Fibrosis treatment: inject healthy alleles for the Cystic Fibrosis gene into
the viruses then sprayed them into patients’ nose/mouth. Virus infects cell and
injects these healthy genes into the human cell to help symptoms.
Restriction Fragment Length Polymorphism (RFLP):
DNA is cut into small pieces, put through gel, and then a probe is used to
identify sequence of nucleotides. Different individuals have different RFLPs in
their DNA and can be used for identification.
Human Genome Project
- A human cell contains 46 chromosomes that have 3 billion pairs of DNA
nucleotides. The Human Genome Project is a worldwide effort to identify the
complete nucleotide sequence in humans.
- This will help identify genes associated with genetic disorders
BLOOD TYPES:
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Part 2 Questions- Written Responses
- Diagram of plant and animal cells, which structures would be found in one and not the
other
- Differences between asexual and sexual reproduction
- Scientific Method, remember hypothesis is a statement not a question!
- Microscope movement
- Enzyme substrate picture, lock & key fit
- Mitosis vs Meiosis diagrams and written differences
- Photosynthesis & Respiration equations. Trace energy flow.
- DNA code conversion to amino acids. Mutagens that can cause mutations.
- Graph
- Diffusion Lab
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