Gene Test Concept 3 SG Flashcards
Diploid
2 full sets of chromosomes (2n); 1 set from mom, 1 set from
dad
Haploid
1 full set of chromosomes (n); 1 set that is a combination of
chromosomes from mom and dad
Karyotype
Diagram that shows the number and visual appearance of the
chromosomes in a cell
Meiosis
The process of cell division that makes gametes in the gonads
for sexual reproduction
- Sexual reproduction
The fusing of genetic information (gametes) from two parents
to produce offspring that are a genetic mixture of both parents
*Fertilization
- The actual fusion of egg and sperm to form a zygote
*Homologous chromosomes
- Chromosome pairs that have the same types of genes (1
from mom and 1 from dad)
Sister chromatids
2 identical copies of the same chromosome
Describe the difference between somatic cells and
gametes.
Somatic cells are body cells that are diploid, meaning
they have full copies of DNA (2 complete sets) in each
cell.
* Gametes are sex cells (egg and sperm) that are
haploid, meaning each cell only has half of the DNA (1
complete set).
Differentiate between autosomes and sex
chromosomes.
- Autosomes are chromosomes that carry traits that make
you who you are. - Ex. In humans, chromosomes 1-44
- Sex chromosomes are chromosomes that specifically
determine biological sex. - Ex. In humans, chromosomes 45-46
Explain why cells going through meiosis must divide
twice.
Because the purpose of meiosis is to make cells for sexual reproduction,
the resulting cells need to have half the amount of DNA,
since they will hopefully later fuse during fertilization to make offspring.
what would happen if cells only divided once through meiosiss
- If the parent cell only divided once, the resulting cells would have
the same amount of DNA as the parent cell, and thus the zygote
would end up with way too much DNA.
Differentiate between the purpose and results of meiosis
I and meiosis II.
- Meiosis I = purpose is to separate homologous chromosome
pairs, so the result is 2 haploid cells that still have duplicated
chromosomes (sister chromatids). - Meiosis II = purpose is to separate sister chromatids, so the
result is 4 haploid daughter cells with unduplicated
chromosomes.
Explain the significance of crossing over.
It creates new combinations of genes, with recombinant DNA
that is part mom and part dad.
Summarize the key differences in purpose and
results of meiosis and mitosis.
- Meiosis = purpose is to make haploid gametes with half
the amount of DNA for sexual reproduction. - Mitosis = purpose is to make identical diploid body
cells to the parent cell for growth and repair.
Explain the difference between a mistake made
during meiosis and a mistake made during mitosis.
- A mistake made in meiosis would be passed on to
potential offspring in an egg or sperm. - A mistake made in mitosis would (most likely) only affect
the parent and could result in cancer, or uncontrolled cell division.
Identify a cell as haploid or diploid based on a
description or picture.
ask dr chapmen
Predict a consequence for an error made during
one of the phases in meiosis.
ask
somatic cells
body cells, these are diploid (2n)`
what are blood cells, lung cells, and heart cells
somatic cells
gametes
sex cells
these are haploid (n)
what is eggs and sperms
gametes
diploid cells
2 full sets of chromosomes
2n
a set from mom and a set from dad
in human, somatic cells
each set (one from ___ and one from ___ ) is ____ pairs of chromosomes; this makes its diploid or 2n number ____
mom and dad, 23, 46
haploid cells
1 full set of chromosomes
n
only one set and it is a combonation of chromosomes from mom and dad
autosomes
a type of chromosomes that carries traits that make you who you are (the first of the 22 pairs of chromosomes in a cell)
sex chromosomes
carry trait that make you who you and AND determined your biological sex
(the 23rd pair)
what chromosome pair is the 23rd pair if male/female
male XY
female XX
meiosis 1
prophase 1
- nuclear membrane breaks down
- Chromosomes match up with their homologous pairs.
- when they become lined together sometimes chromosomes cross over each other and get “tangled” they swap pieces of DNA to create new combinations of genes (chromomses that are part mom, part dad)
metaphase 1:
- homologous chromosomes are lines up in the middle of cell in pairs (M in metaphase stands for middle)
Anaphase 1:
- homologous chromosomes pairs separate one chromosome (2 sister chromatids) pulled away to each sides
- a in anaphase mans away
Telophase1:
- chromosomes gather at poles, nuclear membrane may reform
- cytokinesis: the cytoplasm divides into 2 cells
the result is 2 haploid daughter cells with duplicated chromosomes that are different from the sets in the original diploid cell.
before meiosis 1, what happens?
interphase, the growth phase of the cell cycle
G1: cell grows and makes proteins
S Phase: DNA Replication doubling the number of chromosomes
G2 Phase: more cell growth and protein synthesis
at the end of interphase the cell has duplicated copies of every chromosome
meiosis 2
prophase 2
-nuclear membrane breaks down
-spindle fibers attach to the centromeres of the sister chromatids
metaphase 2
-sister chromatids line up in the middle of the cells single file
anaphase 2
-sister chromatids separate and are pulled away from eachother to each sides of the cells
telophase 2
-nuclear membranes form aorund each set of chromosomes
- cytokenesis: cytoplasm divides each cell into a cell
end result: 4 halpid daughter cells that are genetically unique
when does meiosis happen in males
throughout life (starts in puberty)
when does meiosis happen in females
in the womb before you were born
where does meiosis happen in females / men
ovaries and testes
why is their meiosis
to make babies
type of reproduction for meiosis/mitosis
MIT: asexual
MEI: sexual
