BIOL101: Ch. 8 - Cellular Reproduction

Spermatogenesis

The formation of sperm

Oogenesis

The formation of eggs

4 haploid sperm

How many functional sperm are made?

1 haploid egg

How many functional eggs are made?

1 and polar bodies

Meiosis in females makes ___ eggs and 3 ____ _____

Prophase I

In which phase of meiosis does crossing over occur?

Homologous chromosomes

Is information swapped between homologous chromosomes or sister chromatids?

Chiasma

The site of crossing over is called

Random

Is the alignment of chromosomes at metaphase 1 programmed or random?

Random

Can we predict which sperm will fertilize an egg or is it random?

Monosomy

Is a genetic condition where a cell is missing one chromosome from a pair; a type of aneuploidy

Missing chromosome

Is monosomy resulting from an extra chromosome or missing chromosome?

No

Will a human embryo survive if there is a missing autosome?

Yes only if it’s not an X chromosome missing

Will a human embryo survive if there is a missing sex chromosome?

Specific ones like trisomy 21 (down syndrome), trisomy 18 (Edwards), and extra sex chromosomes

Do all trisomies result in viable embryos or are there only specific ones that can survive?

Non-disjunction

If members of a chromosome pair fail to separate

homologous chromosomes

If there is non-disjunction in meiosis 1, ______ fail to separate

sister chromatids

If there is non-disjunction in meiosis 2, _______ fail to separate

Down Syndrome

Is the most common number abnormality and results from extra chromosomes; is trisomy 21

Intellectual disabilities, short stature, heart defects, alzheimer’s disease, shorter life span

What are the features of Down syndrome?

Trisomy

Is it a trisomy or monosomy?

Down syndrome, Edward syndrome, and extra sex chromosomes

Which chromosome are there 3 of?

Yes

Could you recognize this down syndrome on a karyotype?

Mother age 44

Who has a higher chance of having a Down syndrome child: mother age 22, mother age 44?

2 genetically identical daughter cells

How many cells are produced by mitosis?

4 haploid cells

How many cells are produced by meiosis?

Yes

Are the cells produced by mitosis genetically identical?

No

Are the cells produced by meiosis genetically identical?

Diploid

Are the cells produced by mitosis haploid or diploid?

Haploid

Are the cells produced by meiosis haploid or diploid?

Genetically unique

Does meiosis produce gametes that are genetically identical to the parent cell?

Equal mix of genetic information from each parent

Do all chromosomes in the offspring come from one parent or is there an equal mix of genetic information from each parent?

Sperm

What is the male gamete?

Testes

Where are gametes made in males?

Egg

What is the female gamete?

Ovaries

Where are gametes made in females?

Meiosis

Which process forms gametes: mitosis or meiosis?

half

A gamete has ____ the number of chromosomes found in the parent cell.

Fertilization

Is the fusion of two haploid gametes (sperm and egg) to form a zygote (single diploid cell)

Zygote

The fertilized egg

Haploid (n)

If there is only a single set of chromosomes, the cell is this; has only one copy of each chromosome

Diploid (2n)

If chromosomes are in homologous pairs, the cell is this; has 2 copies of each chromosome

Gametes

Which cells are the results of meiosis?

We use mitosis for growth, tissue repair, replacing old/damaged cells in multicellular organisms

When do we use mitosis?

Egg and sperm and adults

When in the life cycle are cells haploid?

Zygote and baby(ingrid)

When in the life cycle are cells diploid?

The sperm and egg form a zygote

What happens at fertilization?

A zygote is the single cell formed when a male sperm fertilizes a female egg

What is a zygote?

16

If a haploid gamete has 8 chromosomes, how many in the diploid cell?

23

If a 2n cell has 46 chromosomes, how many in the haploid cell?

Homologous Chromosome

Contain genes for the same traits but are not identical

Allele

Is one of two or more alternative forms or versions of the same gene; influences traits

Sister chromatids

Two identical, duplicated copies of a single chromosome; formed after DNA replication during S phase

Interphase (S phase)

When is the DNA copied for meiosis?

Meiosis I (Prophase I)

When does crossing over take place?

Meiosis I

When do homologous chromosomes separate: meiosis 1 or 2?

Meiosis II

When do sister chromatids separate: meiosis 1 or 2?

Homologous chromosomes line up in pairs and crossing over occurs

What happens during prophase 1?

Chromosomes line up in the middle of the cell

What happens during metaphase 1?

Homologous chromosomes are pulled to opposite poles

What happens during anaphase 1?

Separated homologous chromosomes arrive at opposite poles, nuclear envelopes reform around them, spindle apparatus disassembles, cell begins to split

What happens during telophase 1?

Cells have 1 chromosome from each homologous pair; they begin to line up with their pair

What happens during prophase 2?

Chromosomes align at the metaphase plate

What happens during metaphase 2?

Sister chromatids separate and become daughter cells

What happens during anaphase 2?

Spindle disappears, nuclei form, and cytokinesis takes place

What happens during telophase 2?

Sister Chromatid

When DNA copies the two identical chromosomes

Centromere

The sister chromatids are linked by a structure called the

Kinetochore

The spindle fibers will attach at here during mitosis:

Centrosome

The spindle fibers grow from centrioles which are anchored at the

1

One chromosome has ___ DNA double helix

1

Sister chromatids have __ DNA double helixes?

Nearly Identical

Are the two double helices of sister chromatids identical or different?

92

If we start with 46 chromosomes, how many sister chromatids are present after the S-phase of mitosis?

16

If a non-human cell has 16 chromosomes after the S-phase of mitosis, how many were there originally?

Nuclear membrane breaks down and the spindle fibers start to assemble

What happens during prophase?

Yes

Are spindle fibers microtubules?

Sister chromatids line up in the middle of the cell

What happens during metaphase?

Sister chromatids are pulled to opposite sides of the cell

What happens during anaphase?

Nuclear membrane begins to reform and the chromosomes begin to uncoil

What happens during telophase?

The two daughter cells physically separate and is the final separation

What happens in cytokinesis?

Animal cells

Which has a cleavage furrow/division furrow?

Plant cell

Which has a cell plate?

Checks for nutrient availability or social signals

What is being checked for at the G1 check point?

Checks for DNA damage

What is being checked for at the G2 check point?

Checks if chromosomes are properly attached to the spindle fibers

What is being checked for at the M check point?

Due to a lack of growth signals or nutrients or severe DNA damage

What triggers a cell to go into G0?

Neurons, skeletal and cardiac muscle cells

Name some human cells that are in G0?

Protects the ends of chromosomes to prevent DNA from fraying, sticking to other chromosomes, or being mistaken for damaged DNA by the cell’s repair systems

What is the function of telomeres?

The telomeres shorten

What happens to the telomere each time a cell divides?

No, they usually pause the cell cycle to allow for repair (G2)

Will cells with damaged DNA be allowed to complete the cell cycle (think checkpoints)

Telomerase

Cancer cells have a special enzyme called

Repair telomeres

The function of telomerase is to:

Benign

Which would you rather have a benign or malignant tumor?

Cancer

Is a disease of uncontrolled cell proliferation

Cancer (Detailed One)

Is a loss of cell cycle regulation and far too many copies of cells are made

Tumor

The extra cells that were made which form a ball

Benign

The extra cells are harmless and do not spread

Malignant

The tumor cells are dangerous and can spread outside of their original location, either to local or distant regions

Interphase (Meiosis I)

Label this

Prophase I (Crossing over happens here)

Label this