IB Cell Cycle, DNA, and DNA Replication

Diploid

-2n -2 copies of each chromosome -somatic/body cells

Cyclins

-Bind to cyclin dependent kinases to activate them -Cyclin complexes bind to target proteins activate them to start the next phase of the cell cycle -Different cyclins produced at different times bind to specific cyclin dependent kinases to ensure the cell cycle in proper sequence at the proper rate

What occurs during prophase?

-Chromatin (DNA and chromosomes) condenses and chromosomes become visible -Nucleolus disappears -Nuclear membrane breaks down -Mitotic spindle forms -Centrosomes move away from each other to opposite ends of the cell

What occurs during metaphase?

-Chromosomes align on the metaphase plate -Spindle fibers attach to the centromere of each chromosome

What occurs during telophase?

-Chromosomes gather at the poles of the cell -Mitotic spindle disappears -Two nuclear membranes form -Chromosomes decondense

Cell cycle controls

-Cyclins -Genes

Eukaryotic Cells

-DNA associated with proteins -DNA is linear -DNA in nucleus -DNA contains introns -Membrane bound organelles -80s ribosomes -larger BOTH HAVE - DNA, Cell Membrane, Cytoplasm, Ribosomes

Mutagens

-Radiation: UV Radiation, X-rays -Chemicals: Smoke, BBQ, Nitrate preservatives, Benzoyl Peroxide -Infectious Agents: Viruses, Bacteria

What takes place in animal cells during cell division?

-Re-formation of nuclear membranes -DNA replication -Cleavage furrow

Benign Tumor

-Remain at the original site -Contained within a membrane

What occurs during anaphase?

-Sister chromatids separate at the centromere -Centromeres divide -Spindle fibers contract pulling one copy of each chromosome to each opposite ends of the cell

Nitrogenous Bases

-Thymine (T) -Adenine (A) -Cytosine (C) -Guanine (G) (T->A and G-> C)

Genes

-Tumor suppressor genes (makes proteins to inhibit cell growth/division when activated) -Oncogenes (make proteins that promote cell growth/division when activated)

Endodymbiotic Theory

-a prokaryotic cell engulfed (through endocytosis) a heterotrophic cell -symbiotic relationship formed EVIDENCE -have two membranes -have their own ribosomes -have their own DNA -about the same size as prokaryotic cells

What occurs during interphase?

-about 90% of the cell cycle -produces porteins (transcription/translation) -carries out metabolic reactions -increases number of mitochondria/chloroplasts/other organelles -G1 (first growth) -S-Phase (DNA replication) -G2 (second growth)

Plant Cells

-cell walls -chloroplasts -carbs stored as starch -no centrioles -no cholesterol in cell membrane -large, central vacuoles

Antiparallel

-double helix -left side starts with 5' end -right side starts with 3' end

Nucleosome

-fundamental unit of DNA packaging in eukaryotic cells -8 histone proteins (+ charged) make the core -A DNA stand (- charged) wraps around the core twice -9th histone protein (H1) attaches to hold the DNA in place around core -form along a single molecule of DNA -"beads on a string"

Cell Theory Exceptions

-groups of cells -viruses -some tissues are not just made out of cells -first cells

Complementary base pairing

-hydrogen bonds with A->T and C->G -proper base incorporation into DNA strand -ensures that there are identical copies of the DNA strand

Surface Area to Volume Ratio

-more surface area equals more nutrients, oxygen, etc. -volume determines the rate of heat and waste production and consumption -cells with a smaller ratio, are able to move more waste and head of of the cell and more resources into the cell

Haploid

-n -1 copy of each chromosome -gametes/sex cells (eggs/sperm)

Prokaryotic Cells

-naked DNA (no proteins) -circular DNA -DNA in nucleoid -70s ribosomes -smaller BOTH HAVE - DNA, Cell Membrane, Cytoplasm, Ribosomes

Animal Cells

-no cell walls -no chloroplasts -centrioles -small, if any vacuoles -carbs stored as glycogen -cholesterol in cell membrane

Structural sequences

-no protein-coding function -highly coiled sequences -occur at the centromere and telomeres of chromosomes -aid in maintaining the structure of DNA -pseudogenes appear to be structural sequences providing support in DNA molecules

Mitotic Index

-number of cells in mitosis/total number of cells -cells are dividing at a higher rate (cancer)

Highly repetitive sequences of DNA

-occurs multiple times in genome -no protein-coding functions -introns -not genes -larger differences -short sequences

Protein-coding sequences

-occurs once in genome -protein-coding functions -exons -genes -small differences -long sequences

Water

-polar -hydrogen bonds -cohesive properties (water to water) -adhesive properties (water to something else) -thermal properties (high specific heat) -solvent properties ("like" dissolves "like")

Number of sister chromatids after anaphase

0

Cell Theory

1. All organisms are composed of one or more cell 2. Cells are the smallest units of life 3. All cells come from pre-existing cells

How does replication happen?

1. helicases unzips the double helix, breaking the hydrogen bonds between the bases 2. gyrase and single-strandbinding proteins stabilize the unzipped DNA 3. primase adds a sequence of RNA bases to each parental DNA molecule at the replication origin (primer) 4. DNA polymerase III adds new nucleotides to the RNA primer to create a new complementary strand (leading strand is continuous, while lagging strand through Okazaki fragments) 5. In the lagging strand, DNA ligase fills the gaps between fragments 6. DNA polymerase I removes RNA primers and replaces them with DNA nucleotides (except at the tip of the 5' end)

Number of chromosomes at the beginning of interphase

2n

Number of chromosomes in each daughter cell after mitosis

2n

Number of sister chromatids after the S-phase of interphase

4n

Which direction is DNA assembled?

5' to 3' direction

What is a difference between a cell in the G1 phase and a cell in the G2 phase of the cell cycle?

A cell in the G2 phase would have more mitochondria than a cell in the G1 phase

What is the composition of the backbone of DNA?

Alternating sugar and phosphate molecules

What are the four most common elements in living systems

C - carbon H - hydrogen O - oxygen N - nitrogen

How do plants complete the cell cycle?

Cell Plate formed by vesicles

What type of bonds connect the phosphate and deoxyribose?

Covalent bonds: Phosphodiester bonds

What occurs during cytokinesis?

Cytoplasm divides forming two genetically identical daughter cells

Pyrimidine Bases

Cytosine (C) and Thymine (T) -single-ring structures

What does a nucleosome consist of?

DNA and histones

In the structure of DNA what binds with cytosine?

Deoxyribose

What are the components of a DNA nucleotide?

Deoxyribose, a phosphate, one of the bases

Passive Transport

Diffusion, Osmosis, Facilitated Diffusion -does not require ATP -goes down in concentration gradient -substances move from areas of high concentration to low concentration

Active Transport

Endocytosis, Exocytosis, Pinocytosis, Phagocytosis -require ATP -goes up in concentration gradient -substances move from areas of low concentration to high concentration

What type of bonds connect nucleotides?

Hydrogen bonds -T->A (2 bonds) -G-> C (3 bonds)

What are homologous chromosomes

Non-identical chromosomes with the same genes in the same sequence but not necessarily the same alleles

In the Hershey and Chase experiment what observation led to the conclusion that DNA was the genetic material?

Radioactive phosphorus was found in the pellet

What happens during the G2 phase of interphase?

Synthesis of proteins

How can cells in a multicellular organism differentiate?

They express some of their genes but not others

Semiconservative

When DNA is replicated, the two new DNA molecules both consist of an original, parent strand, and a newly built daughter strand -one of the original parent strands is maintained in each of the new DNA molecules -Meselson and Stahl experiments -5' to 3' direction

What are Hydrolysis reactions?

When one subunit of a macromolecule is hydrolysed from another, a molecule of water is split to break the covalent bond between the subunits -water is always a reactant

What are condensation reactions?

When one subunit of a macromolecule is joined to another, a molecule of water is removed, and the subunits are joined by covalent bonds -water is always a product

Metastasize Tumor

if they reach blood vessels, they can move to other parts of the body where they can form secondary tumors

Malignant Tumor

invade surrounding tissues

Cancer

uncontrolled cell division

Organic

compounds containing carbon and found in living organisms

Purine Bases

Adenine (A) and Guanine (G) -double-ring structures

Magnification

Mag=M/A