Cell Unit Test Review

Location of the Three Atomic Particles

* neutron
* electron
* proton

Scientific Models

* representation of how something looks or works based on a hypothesis or theory
* 440 BC Democritus said atom was a solid, unbreakable ball
* 1898 Thomson said atoms have positive and negative charges
* 1911 Rutherford determined that atoms have a hard, massive center
* 1913 Bohr added to Rutherford’s model saying that electrons moved around the nucleus
* current one based on Einstein’s work (E=mc^2) = atom is made of a central, positively charged energy cloud and has an outer, negatively charged energy cloud.

How to find number of atomic particles an atom has

\# of Protons = Atomic Number

\# of Electrons = Atomic Number

\# of Neutrons = atomic mass rounded to the nearest whole number

Bohr Model Example: Calcium

Why do atoms make bonds?

Atoms make bonds to balance their valence shells.

Either collect more electrons or drop electrons.

Become stable and decrease energy

Types of Atomic Bonds

Covalent Bonds: two or more atoms share electrons

* most common
* strongest

Ionic Bonds: Ions of opposite charges are attracted and form a bond

Hydrogen Bonds: Weak attraction between hydrogen on one molecule and another atom on the same or different molecule

Bohr Model of Water

* show shared electrons

Define:

* atom
* molecule
* element
* compound

Atom: Smallest particle of an element that has the characteristics of that element

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Element: simplest form of matter.

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Molecule: Two or more atoms chemically combined

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Compound: A molecule made of 2+ different types of atoms

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Atoms are made of elements

Molecules and compounds are made of atoms

Molecule Models of:

* Sugar (monosaccharide)
* amino acid

Molecule Models of:

* fatty acid
* glycerol
* nucleotide

What elements comprise and what is the structure of a **single sugar**?

* rings of carbon and one oxygen
* each carbon has a hydroxyl group and a hydrogen bonded onto it

What elements comprise and what is the structure of an **amino acid**?

* carbon, hydrogen, oxygen, nitrogen
* building blocks of proteins
* made of an amino group, organic acid group, variable group

What elements comprise and what is the structure of a **fat/lipid**?

* made of carbon and oxygen with hydrogen bonded to each carbon

**Saturated Fats**

* have no double bonds
* had all the hydrogen atoms it can hold bonded to it

**Unsaturated Fats**

* one or more double bonds
* carbon doesn’t have all hydrogen possible bonded to it

What elements comprise and what is the structure of a **nucleotide**?

* made of carbon, hydrogen, oxygen, nitrogen
* single or double ring structures of carbon and nitrogen with amine groups, methyl groups, or oxygen bonded to the rings

What do the suffixes mean?

\-ose

\-ol

\-ase

\-ine

\- ose means sugar

\- ol indicates fat

\- ase indicates an enzyme

\- ine indicates an amino acid

What smaller molecules (monomers) make up this macromolecules (polymers)?

* starch (polysaccharide)

* made of glucose
* two glucose molecules do a dehydration reaction to become maltose to become starch

What smaller molecules (monomers) make up this macromolecules (polymers)?

* fat

* made of glycerol and three fatty acids
* bonded by an ester bond

What smaller molecules (monomers) make up this macromolecules (polymers)?

* proteins

* made of amino acids
* bonded with a peptide bond

What smaller molecules (monomers) make up this macromolecules (polymers)?

* DNA

* made of nucleotides
* important for storing energy
* 3 carbon of sugar has hydroxyl group

Chemical Groups

What is an enzyme?

What is it made of?

How are enzymes the workers of the cell?

* catalyst made of proteins
* called “workers of the cell” because they
* increase the speed of the chemical reactions but **aren’t used up/changed in the reaction**
* each enzyme **works on a specific substrate**/has a specific job

What is the Kinetic Molecular Theory and what does it have to do with the speed of the reaction?

* KMT states all matter vibrates/moves and increasing energy (heat) will increase vibration (movement).
* if the substrates/enzymes move faster, they will collide at an increased rate
* increases the rate of reactions

How does induced fit/lock and key method work?

1. enzyme and substrate join together
2. enzyme “tweaks” the substrate so a bond is made/broken
3. enzyme and substrate break apart

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Reaction happens much faster with enzymes than without

**Hydrolysis Reaction**

* **breaks apart** molecules
* catabalesm
* two molecules that had been joined + a water molecule are split apart with water joining the now separated molecules as OH groups

**Dehydration Reaction**

* **bonds 2 molecules together**
* removes H20 (water)
* an anabolism
* an H is removed from one molecule and an OH from another molecule and the two molecules are joined together at an O
* results in a macromolecule and a water molecule

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**DEHYDRATION = JOINING by REMOVING WATER**

Hydrolysis vs. Dehydration

Hydrolysis = macromolecules become smaller

Dehydration = smaller molecules become bigger/macromolecules

**pH Definition**

*negative log of the concentration of hydrogen ions in a solution*

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* acidic = more H+ than OH-
* basic/alkaline = more OH- than H+
* neutral = equal number

pH ranges

>7 = Acidic

7= Neutral

What conditions does amylase work best and is it the same for all enzymes?

* amylase should work best in warm areas with a neutral to basic pH
* working better at warmer temperatures is the same for all enzymes because of KMT

What occurs in the cell cycle between mitotic divisions?

The cell goes through three other phases. Synthesis (S), Gap 1 (G!) and Gap 2 (G2).

What happens in Gap 1?

* cell experiences metabloic changes to prepare the cell for division
* cell builds more contents and doubles all contents except chromosomes
* at restriction the cell is committed and can’t get back

What happens in synthesis?

* the cell constructs a second full set of chromosomes through DNA synthesis
* each chromosome is now made of two sister chromatids

What happens in Gap 2?

* cytoplasmic materials are assembled
* cell checks for errors and makes repairs
* then the cell can move onto mitosis

What are G1, S, and G2 called collectivly?

Interphase

What are the phases of mitosis?

1. interphase
2. metaphase
3. anaphase
4. telophase
5. cytokinesis

What happens in interphase?

Interphase is **stage one** of **mitosis**.

* chromosomes duplicate with copies remaining attached

What happens in prophase?

Prophase is **stage two** of **mitosis**.

* nucleolus and nuclear envelope break apart
* spindle begins attaching to the chromosomes

What happens in metaphase?

Metaphase is **stage three** of **mitosis**.

* the chromosomes are pulled to the center of the cell
* aligns with the equatorial plane

What happens in anaphase?

Anaphase is **stage four** of mitosis

* the two identical chromatids of each chromosome seperates
* pulled by centromeres to the opposite ends of the cell

What happens in telophase?

Telophase is **stage five** of mitosis.

* spindle breaks down
* allows chromosomes to spread out
* nuclear envelope and nucleolus are reforming
* cytoplasm may be starting to divide

Basically reversing prophase

What happens in cytokinesis?

Cytokinesis is the **last stage/stage six** of mitosis

* actual cell division
* divides into two identical daughter cells
* nucleus and nucleolus are evident
* chromatin are not
* cells are identical to parent cell, but 1/2 the size

What is mitosis?

* type of nuclear division
* results in 2 exact copies of DNA and then 2 identical daughter cells (formed during cytokinesis)
* occurs in somatic (body cells)
* occurs to maintain body cells to perform their function
* allows cells to repair, develop, grow

What is DNA?

Deoxyribonucleic Acid

* genetic material for all living things
* formed in the nucleus
* double helix
* made of phosphate and sugar
* sides of the ladder
* paired bases
* Adenine and Thynine (AT)
* Guanine and Cytosine (GC)

What monomers make up DNA? How are they arranged?

Nucleotides

* made of sugar/deoxyribose
* phosphate
* bases

How are the “steps” of the ladder bonded? (paired bases)

* covalent bonds

How are the uprights of the ladder bonded? (phosphate and sugar)

* hydrogen bond

Where does DNA replication occur?

* nucleus

When does DNA replication occur?

* S phase of interphase

What happens in DNA replication?

* exact copies of DNA are made
* like copying a book

What are the steps of DNA replication?

1. enzymes open up the double helix


1. breaking hydrogen bonds between the bases
2. Enzymes separate the base pairs and expose the bases to the nucleoplasm


1. nucleoplasm contains more nucleotides
3. other enzymes bring in new nucleotides with the correct paired bases to the open DNA helix
4. nucleotides are covalently bonded together


1. forms sugar/phosphate backbone
5. as enzymes move down the DNA strands, two identical double helixes are formed


1. one goes to each cell

Why do bases pair?

* allows DNA to be copies accurately *every time it is replicated*

Where does transformation occur?

* ribosomes
* cytoplasm

When does transformation occur and what is it?

* Happens as DNA replication occurs
* is DNA being copied into mRNA

What are the steps of transformation?

1. initiation


1. ribosomes, tRNA, and mRNA come together
2. tRNA anticodons align with H-bonds mRNA codon
3. start codon is methionine
2. Elongation


1. second tRNA with a second anticodon attaches to the next mRNA codon

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Then the ribosome moves down the RNA by one codon

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3. a third tRNA aligns


1. amino acids 1 and 2 are bonded and the original tRNA is released


1. tRNA goes back to cytoplasm for another amino acid

continues for the length of the mRNA

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4. Termination


1. stops the process
2. once ribosome reaches a “stop” codon the protein is complete


1. mRNA, tRNA, and rRNA are released

Multiple rRNAs can read the mRNA at once

* each makes a copy of the protein

Where does transcription occur?

* in the nucleus

What are the steps of transcription?

1. Helicase opens DNA helix


1. breaks hydrogen bonds for one gene length


1. bases are exposed to nucleoplasm
2. enzyme brings in the complimentary RNA nucleotides


1. sugar and phosphate are covalently bonded
3. DNA closes, mRNA leaves the nucleus and goes to the ribosomes in the cytoplasm or on the endoplasmic reticulum.

Why is it ensured that the correct amino acid will be put into a protein?

* base pairing

What is meiosis?

* cell division in which the number of chromosomes in each daughter cell is reduces to 1/2 the number in the parent cell
* produces **gametes** (sex cells)
* haploid

Somatic vs. Gametes

**Somatic**: diploid, body cells

**Gametes**: haploid, sex cells

Chromosome

* rod shaped structure
* visible during mitosis and meiosis
* contains one long DNA molecule and proteins

Gene

* section of DNA found on chromosomes
* contains information for one protein or trait

Allele

* alternate forms of a gene or two genes on homolgous chromosomes
* contains information for the same trait

Heterozygote

* pairs of genes for a given trait


* alleles are **different**

Homozygote

* pairs of genes for a given trait
* alleles are **identical**

Phenotype

* physical characteristics of a trait
* how gene is expressed

Genotype

* gene combination for a trait

Homologous chromosomes

* pairs of chromosomes
* have DNA that codes for the same traits
* same genes in the same sequence
* one pair from each parent

variation

* individuals with a wide variety of traits

Crossing over

* exchange of gentic material between homologous chromosomes during meiosis

Gametes

* sperm or egg
* produces in the gonads

What is a dominant trait?

* trait expressed in phenotype, expressed physically

What is a recessive trait?

* contained in genotype but is __not__ expressed physically

What is an autosomal trait?

* trait controlled by any chromosome that is __not__ a sex chromosome

What is a sex linked trait?

* trait in which the gene is on a sex chromosome (usually X chromosome)

Zygote

* fertilized egg

Embryo

* germ laywes are formed but organs are not

Fetus

* organs are designated
* pre-natal

How are zygotes, gametes, and fetuses related?

* Gametes are sex cells which combine to become a fertilized egg
* after cell replication the zygote becomes an embryo
* cells continue to replicate and the embryo becomes a fetus

What are Mendel’s Four Principles of Inheritance?

1. traits are controlled by paired factors (genes) with one from each parent
2. a dominant gene masks a recessive gene hiding its presence


1. 2 types of dominance


1. complete
2. incomplete
3. paired genes are separated in the parents when gametes are formed during meiosis (segregation)
4. Independant assortment


1. all different genes are distributed to the gametes in a random order

How did Mendel test his theory?

* bred thousands of pea plants
* found purebred pea plants od the same tupe resulted in offspring with the same genotype
* tested interbred pure plants of two types they were tall 100% of the time with genotype of Tt
* when 2 crossbreds were interbred, 75% were tall, 25% were short

How is recombinant DNA formed?

* formed when DNA fragments of more than one organism are combined

How is recombinant DNA formed?

* A plasmid and recipicient are needed
* gene is cut out of both (same gene, different alleles)
* leaves “sticky ends”
* DNA from plasmid is input into the recipicient

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needs to be in a vector, for example a retrovirus

Metabolism

Sum of breaking down and building up processes in the body

Anabolism

Building up processes

* mitosis, photosynthesis, making macromolecules

Cell Diagram Examples

Endothermic creatures

* control own body temperature
* mammals and fish
* insulation is used to prevent heat loss
* uses metabolism to make heat

Exothermic

* gets body temperature from the environment
* fish, amphibians, reptiles, invertebrates
* no insulation
* dependant on outside temperatures

Where does photosynthesis take place?

In the palisade mesophyll inside choroplast

What is photosynthesis?

* light energy is converted into chemical energy stored in bonds of glucose
* 2 different phases

What is the summary reaction of photosynthesis?

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What are the two phases of photosynthesis?

Light reaction

Dark reaction

What is the light reaction of photosynthesis?

* converts H20 and light energy into oxygen
* water is split releasing H+, e- and O2.
* H+ and e- are kept for next reaction
* O2 is released

What is the dark reaction of photosynthesis?

* converts CO2 into glucose
* inorganic carbon (CO2) is converted into organic carbon (glucose) which is stored as energy

What is ATP?

**A**denosine **T**ri**p**hosphate

* energy source for all activities in living things

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To release energy from ATP, **last phosphate is broken off**

Where is cellular respiration and glycolysis taking place?

* mitochondria of the cells
* all cells

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Takes place in almost all organisms

* except some yeast and bacteria

What happens in glycolysis?

* glucose is split and **2ATP** is captured
* occurs in cytoplasm

What is the summary equation for glycolysis?

C6 H12 O →2C3 H4 O3 4H + E (**2ATP**)