What is in the Domain Eukarya Kingdoms Animals

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What is in the Domain, Eukarya? Kingdoms: Animals, Fungi, Plants and Protista (everything else)

What is in the Domain, Eukarya? Kingdoms: Animals, Fungi, Plants and Protista (everything else)

When did eukaryotic Cells appear? ~2 billion years AGO and ~1. 7 billion years

When did eukaryotic Cells appear? ~2 billion years AGO and ~1. 7 billion years AFTER prokaryotic life evolved Where did they come from? Guess.

Where did Eukaryotic Cells Come From? *Not a separate chemical evolution event *Evolved from

Where did Eukaryotic Cells Come From? *Not a separate chemical evolution event *Evolved from a prokaryotic cell *increased cell size meant problems. Fig. 7. 6 a Eukaryotic cell Eukaryotes cells are 10 X’s larger in diameter & filled with membrane-bound organelles Prokaryotic cell

Organelles provided increased energy to a cell, giving them a survival and reproductive advantage

Organelles provided increased energy to a cell, giving them a survival and reproductive advantage so natural selection favored them. I. To get more energy, cells could A. Eat more food molecules B. Have a more efficient way to break down food for energy A. Eating: take in Small molecules that can pass membrane like sugar monomers B. ATP In prokaryotes

A. Eat more food by eating larger food particles (more glycolysis) This works when

A. Eat more food by eating larger food particles (more glycolysis) This works when there are smaller compartments inside cell to break down larger ingested food into molecules that can be used in glycolysis Most eukaryotic cells cannot eat by phagocytosis, so how do they meet increased energy demands?

B. Increase efficiency of Food Energy (Cell Respiration) In prokaryotes, cell respiration occurs in

B. Increase efficiency of Food Energy (Cell Respiration) In prokaryotes, cell respiration occurs in the open cytoplasm of the cell (same place as synthesizing new molecules and many other processes are happening) This mess happens… …in here

B. Have a more efficient method of Food Energy (Cell Respiration) Compartments make rxns

B. Have a more efficient method of Food Energy (Cell Respiration) Compartments make rxns more efficient b/c: • reactants run into each other more efficiently • incompatible reactants are separated *= a molecule made in organelle • = an enzyme used in organelle but that degrades * * ⊕ ⊕* * Prokaryote ⊕ ⊕ * * * Eukaryotic cell * ⊕ ⊕ ⊕ * * * ⊕

Membrane Surface area for electron transport chain

Membrane Surface area for electron transport chain

What evidence do we have for endosymbiosis? • Mitochondria have: Circular genomes that replicate

What evidence do we have for endosymbiosis? • Mitochondria have: Circular genomes that replicate independently of chromosomal DNA • Mitochondria can carry out their own transcription and translation (doesn’t need transcription/translation machinery used by nuclear gene expression) • Mitochondria have their own ribosomes (where translation is carried out) that resemble bacterial ribosomes not eukaryotic ribosomes.

What evidence do we have for endosymbiosis? • Mitochondria have double membranes consistent with

What evidence do we have for endosymbiosis? • Mitochondria have double membranes consistent with engulfing mechanism proposed. Membranes from euk cell memb & engulfed prokaryote • Mitochondria are size of avg. bacterium and replicate by binary fission (independent of host cell division)

Same lines of evidence found in chloroplasts… • Also has it’s own circular DNA,

Same lines of evidence found in chloroplasts… • Also has it’s own circular DNA, transcription and translation machinary and ribosomes • Also similar in size and shape to prokaryotes • Also has a double membrane • Ribosomes also more similar in size and composition to prokaryote ribosomes • Also divides by binary fission

Innovations: • Nuclear membrane • Mitochondria • Chloroplasts (plasmids in general)

Innovations: • Nuclear membrane • Mitochondria • Chloroplasts (plasmids in general)

Now that we have eukaryotes – what are they doing? • Respiring • Making

Now that we have eukaryotes – what are they doing? • Respiring • Making more of themselves

The cell cycle orderly sequence of events that occurs from the formation of a

The cell cycle orderly sequence of events that occurs from the formation of a eukaryotic cell through the duplication of its chromosomes to the time it undergoes cell division

The Cell Cycle There a total of four phases in the cell cycle: M

The Cell Cycle There a total of four phases in the cell cycle: M phase and an interphase consisting of the G 1, S, and G 2 phases. • Growing cells cycle between a dividing phase called the mitotic (M) phase and a nondividing phase called interphase. • What happens during interphase?

Interphase The stage in which DNA replication / synthesis occurs is called the synthesis

Interphase The stage in which DNA replication / synthesis occurs is called the synthesis (S) phase.

Interphase G 1 and G 2 (gap phases) organelles replicate and additional cytoplasm is

Interphase G 1 and G 2 (gap phases) organelles replicate and additional cytoplasm is made in preparation for cell division. Gap phases allow the cell to grow large enough and synthesize enough organelles to ensure the daughter cells will be normal in size and function.

Chromosomes Change during the Cell Cycle • Eukaryotic chromosomes consist of DNA associated with

Chromosomes Change during the Cell Cycle • Eukaryotic chromosomes consist of DNA associated with histone proteins. • In eukaryotes this DNA-protein material is called chromatin. • interphase, most chromatin is “relaxed” or uncondensed, forming long, threadlike strands. • After replication during S phase, each chromosome consists of two genetically identical sister chromatids attached at the centromere. • At the start of mitosis the replicated chromosomes condense.

interphase, most chromatin is “relaxed” or uncondensed, forming long, threadlike strands. After replication during

interphase, most chromatin is “relaxed” or uncondensed, forming long, threadlike strands. After replication during S phase, each chromosome consists of two genetically identical sister chromatids attached at the centromere. At the start of mitosis the replicated chromosomes condense.

What is aligned at the cell equator during metaphase? a. Sister chromatids b. homologous

What is aligned at the cell equator during metaphase? a. Sister chromatids b. homologous pairs of chromosomes

Which letter represents sister chromatids?

Which letter represents sister chromatids?

Which letter represents homologous chromosomes?

Which letter represents homologous chromosomes?

Reproduction in Eukaryotes Recall prokaryotes (all single-celled) reproduce by binary fission (asexual) Possibilities more

Reproduction in Eukaryotes Recall prokaryotes (all single-celled) reproduce by binary fission (asexual) Possibilities more complicated now • Reproduction of a single cell which could be • an entire organism (i. e. yeast) • part of a multicellular organism • Reproduction of a multicellular organism

Reproduction in Eukaryotes Two different processes regulating reproduction in eukaryotes Mitosis: evolved first, similar

Reproduction in Eukaryotes Two different processes regulating reproduction in eukaryotes Mitosis: evolved first, similar to binary fission but more complicated b/c of multiple chromosomes Meiosis: even more complicated and nothing like it occurs in prokaryotes

Big picture of Mitosis/Meiosis interplay in organisms we are most familiar with (not true

Big picture of Mitosis/Meiosis interplay in organisms we are most familiar with (not true for many eukaryotes) Fig 11. 1

Mitosis Process where somatic cells divide in 2 ~somatic cells are those that are

Mitosis Process where somatic cells divide in 2 ~somatic cells are those that are not gametes (sperm or egg) Daughter cells are genetically identical to parent cell (unless mutation) Single-celled eukaryotes reproduce asexually by mitosis ~1 mitotic division = new organism Multicellular eukaryotic cells undergo mitosis for: growth, replacement of cells and asexual reproduction (where multiple mitotic divisions make a new organism)

The reason mitosis is more complicated than binary fission is due to difference in

The reason mitosis is more complicated than binary fission is due to difference in how prokaryotic vs eukaryotic DNA is packaged… so what is the difference? Prokaryote genome contained on 1 circular chromosome that is found in cytoplasm (extra genes contained on multiple plasmids, not considered part of the genome) Eukaryote genome contained on multiple linear chromosomes contained in the nucleus

Chromosomes contain tightly-wound DNA wraps around histone proteins chromatin folds up to make chromosomes

Chromosomes contain tightly-wound DNA wraps around histone proteins chromatin folds up to make chromosomes DNA chromatin DNA Cell with multiple, separate chromosomes FYI: human cells have 6 ft of DNA and your cells are small enough to fit 1 million on head of a pin so degree of coiling is impressive

Chromosomes and their Ploidy Number (n) All cells need at least one copy (n)

Chromosomes and their Ploidy Number (n) All cells need at least one copy (n) of each chromosome Sex Cells are Haploid (n) Have 1 copy of each chromosome Copy is EITHER from Mom or Dad After fertilization, zygote has 2 copies = diploid muscle cell neuron Somatic Cells (any other cell type) are Diploid (2 n) Have 2 copies of each chromosome One copy from Mom and one from Dad intestinal cells

Back to Mitosis Prior to Mitosis: Each chromosome is copied (DNA replication) Process is

Back to Mitosis Prior to Mitosis: Each chromosome is copied (DNA replication) Process is very similar to DNA replication in prokaryotes Prokaryote chromosome: • single origin of replication • replication is bi-directional Fig 14. 10 Eukaryote chromosome • multiple origins of replication • replication is bi-directional

After chromosomes are replicated, they align in the center of the cell (still attached)

After chromosomes are replicated, they align in the center of the cell (still attached) 2 n “replicated 2 n” DNA replication *cell doesn’t actually quadruple in size, I made it this big to fit all the chromosomes in aligned *In mitosis, order of alignment is random and doesn’t matter Sister chromatids align Sister chromatids

After chromosomes align, they move to opposite poles of the cell. Then membrane invaginates

After chromosomes align, they move to opposite poles of the cell. Then membrane invaginates and Cell divides Chromosomes moves Cell begins to divide

Chromosomes condense Nuclear envelope breaks down Chromosomes start to align in center of cell

Chromosomes condense Nuclear envelope breaks down Chromosomes start to align in center of cell sister chromatids separate (“ 2 n”) Mitosis complete cell membrane pinches in & cytoplasm Is divided (2 n) nuclear envelope reforms Fig 11. 7

By end of Mitosis “replicated 2 n” cell has given 2 n rise to

By end of Mitosis “replicated 2 n” cell has given 2 n rise to two 2 n cells 2 n Replicated 2 n 2 n In this example, cell has 4 different chromosomes and is 2 n (8 total chromosomes). For each pair, one from parent A and other from parent B The same cell now has a total of 16 chromosomes b/c each of the 8 have been copied One of these is the original (parent) cell. The other is the daughter cell: they

Why do cells/organisms undergo mitosis? 1. Some eukaryotes reproduce by mitosis (1 type of

Why do cells/organisms undergo mitosis? 1. Some eukaryotes reproduce by mitosis (1 type of asexual reproduction) sea sponge (multicellular; multiple mitotic divisions= new organism) budding yeast (single-celled; 1 mitotic division= new organism)

Why do cells/organisms undergo mitosis? 2. Eukaryotes undergo mitosis for growth of organism (2

Why do cells/organisms undergo mitosis? 2. Eukaryotes undergo mitosis for growth of organism (2 cells to 4 to 8 to 16) 2 -cell stage IVF embyro 8 -cell stage IVF embyro http: //www. advancedfertility. com/morula. htm-cell stage embyro

What is the final result of mitosis? a. identical 2 n somatic cells b.

What is the final result of mitosis? a. identical 2 n somatic cells b. genetically different 2 n somatic cells c. identical 1 n somatic cells d. identical 2 n gamete cells

If you inherited a gene for a genetic disorder from your mother that is

If you inherited a gene for a genetic disorder from your mother that is known to be located somewhere on chromosome 12, it will be present _____. a. in all of your somatic cells b. in all of your autosomal chromosomes c. on your X chromosome d. in all of your gamete cells

What is the difference between a chromatid and a chromosome? 1. Chromatids consist of

What is the difference between a chromatid and a chromosome? 1. Chromatids consist of DNA, whereas chromosomes consist of proteins. 2. A chromatid always consists of two linear DNA molecules, whereas a chromosome always consists of just one linear DNA molecule. 3. A chromatid is one half of a replicated chromosome, whereas a chromosome consists of DNA wrapped around proteins in a highly organized manner. 4. Chromosomes are always replicated, whereas chromatids are not.

During what phase of the cell cycle does the DNA become replicated? 1. Immediately

During what phase of the cell cycle does the DNA become replicated? 1. Immediately before mitosis 2. During the first stage of mitosis 3. Immediately after cell division

Mitosis is responsible for what key process in multicellular eukaryotes? 1. reproduction 2. wound

Mitosis is responsible for what key process in multicellular eukaryotes? 1. reproduction 2. wound repair 3. growth 4. All of the listed responses are correct.

Which statement is correct concerning the relationship between chromosomes and genes, chromatin, or sister

Which statement is correct concerning the relationship between chromosomes and genes, chromatin, or sister chromatids? 1. Each replicated chromosome consists of two sister chromatids. 2. Chromatin is a length of DNA in a chromosome that codes for a protein or RNA. 3. Genes are the DNA - protein material that make up entire chromosomes. 4. Each unreplicated chromosome consists of two

Which answer correctly associates a distinctive event in mitosis with the mitotic subphase when

Which answer correctly associates a distinctive event in mitosis with the mitotic subphase when it occurs? 1. Anaphase: Sister chromatids separate. 2. Prophase: Chromosomes are replicated. 3. Prometaphase: Chromosomes complete their migration to the middle of the cell. 4. Telophase: Chromosomes condense.

 • In which mitotic phase do the chromosomes condense and the mitotic spindle

• In which mitotic phase do the chromosomes condense and the mitotic spindle begin to form? 1. Anaphase 2. metaphase 3. prophase 4. telophase

Cell-Cycle Checkpoints • Many protein complexes are involved in regulating the cell cycle. •

Cell-Cycle Checkpoints • Many protein complexes are involved in regulating the cell cycle. • G 1 - most important • G 2 • Metaphase • The three cell-cycle checkpoints prevent the division of cells that are damaged or that have other problems, and they prevent the growth of mature cells that should stay in the G 0 state.

G 1 Checkpoint • This checkpoint determines whether the cell will continue through the

G 1 Checkpoint • This checkpoint determines whether the cell will continue through the cycle and divide, or exit the cycle and enter G 0. • factors affect whether cells pass the G 1 checkpoint: 1. Cell size – large enough to split 2. Nutrient availability – sufficient for growth 3. Social signals from other cells – multicellular organisms 4. Health of DNA –damaged? p 53 initiates apoptosis or pause. p 53 =tumor suppressor protein

Cancer Involves Loss of Cell-Cycle Control • Cancers are thought to arise from cells

Cancer Involves Loss of Cell-Cycle Control • Cancers are thought to arise from cells with defects in the G 1 checkpoint.

G 2 Checkpoint • The second checkpoint is between the G 2 and M

G 2 Checkpoint • The second checkpoint is between the G 2 and M phases. Cells stop growing here if chromosome replication has not proceeded properly or if DNA is damaged.

Metaphase Checkpoint • The third and final checkpoint is during M phase. • Stop

Metaphase Checkpoint • The third and final checkpoint is during M phase. • Stop if the chromosomes are not properly attached to the mitotic spindle. • prevents incorrect chromosome separation that could give daughter cells the wrong number of chromosomes.