BSC 1011 - Unit 2 9/4 Lecture: Fungi Life Cycles

Animal Cell

• Nucleus

• Cytoplasm

• Plasma membrane

Do Fungi have Cell Wall?

Yes

Life Cycle

Series of stages through which organism goes through in entire lifetime (birth to death). Includes reproduction

Haploid Cell # of chromosomes

23 (22 autosomal, 1 sex)

• Only in eggs+sperm

Diploid Cell # of chromosomes

23 pairs (46, AA)

• All body cells

Meiosis

• ONLY in gonads.

• Separates set of chromosomes: each (2) cell gets 23 chromosomes

• meio=half

• Diploid to haploid

• Zygote gets 4 daughter cells

Fertilization

• Gonads meet.

• Haploid to one diploid.

Ploidy

Number of sets of chromosomes in cell:

• Haploid: Hypothetical cell with ONE set of chromosomes

• Diploid: Cell with TWO sets of chromosomes.

• 2n = 2 sets, 4n = 4 sets chromosomes, etc.

Mitosis

Nuclear division with cellular division (cytokinesis). Produces 2 cells with identical # of chromosomes

• Identical copies. Start=end

• Ex. diploid to diploid.

• Daughter cells: resulting cells.

Cell goes through mitosis to:

• grow

• repair damaged tissues

• asexual reproduction

Can you be a female w Y chromosome?

Yes, female is default. If there’s no gene producing enough testosterone to become male, stays female.

Number of chromosomes in human zygote? Mitosis or meiosis?

46 (23 pairs). Meiosis

Meiosis

ALWAYS starts with diploid. Ends with 4 haploid daughter cells.

S: Zygotic type life cycle

1. Diploid Zygote

2. Meiosis (4 haploids)

3. Mitosis (Haploid organism)

4. Haploid Gamete

5. Fertilization of gametes

6. Diploid Zygote

Most fungi

S: Gametic life cycle

1. Diploid organism

2. Meiosis (forms gametes in designated spots)

3. Fertilization of haploid gametes

4. Zygote

5. Mitosis

6. Diploid organism

Humans

S: Sporic life cycles

1. Diploid plant

2. Meiosis

3. Spores (haploid, dormant gametophyte that can germinate at any time)

4. Mitosis

5. Plant produces gametes

6. Fertilization

7. Zygote

8. Mitosis (for diploid organism sporophyte)

Plant sexual reproduction