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Biology- Genetics Flashcards

1
Q

Heredity

A

Passing of traits from parent to offspring

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2
Q

Genetics

A

The branch of biology that deals with heredity and the variation of inherited characteristics

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3
Q

Deoxyribonucleic Acid (DNA)

A

Large complex molecule that carries genetic information in cells.Contains all instructions needed to…
- build cells
- allow them to function
DNA is mostly found within chromosomes in the nucleus. But some can be found in the chloroplast and mitochondria
* - Nuclear DNA: comes from both parents
- Mitochondria: DNA ONLY comes from mom

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4
Q

Gene

A

Segment of DNA that codes for a specific trait. Located at a specific spot on a chromosome (Locus or Loci)

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5
Q

Locus

A

The location of a gene on a chromosome

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6
Q

Chromosome

A
  • Made up of protein and DNA

- vary in number, shape and size among organisms

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7
Q

What are cells identified by?

A

A: the number of each chromosome they have.

  • Diploid: two copies of each chromosome (2 sets) *2n
  • Haploid: one copy of each chromosome (1 set)
  • 1n
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8
Q

Polyploid

A

More than two copies of each chromosome

E.g.-Triploid, tetraploid

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9
Q

Asexual reproduction

A

Single parent produces genetically identical offspring “clone”

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10
Q

Advantages and Disadvantages of Asexual Reproduction

A

ADV: no mate needed, helpful if limited mates, “you know what kind of offspring you’ll get”, not a gamble, quicker

DISADV: Lack of genetic diversity, never a possibility of being “better,” at risk of environmental changes ( ie- new disease, climate change)

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11
Q

Advantages and Disadvantages of Sexual Reproduction

A

ADV: Produces genetic diversity; potential to improve,

DISADV: longer, require more energy and nutrients to produce offspring to attract mate, risk of injury and death
*A GAMBLE!

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12
Q

Cell Cycle

A

Describes the stages of a cells life, includes interphase, mitosis and Cytokinesis

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13
Q

Mitosis

A

The process when a eukaryotic cell divides the genetic material in its nucleus into 2 new identical nuclei

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14
Q

Meiosis

A

A process that contributes to genetic variety. it is the division of germ cells to produce haploid (n)sex cells or gametes. this occurs in the reproductive organs ONLY. Daughter cells will have half the chromosome# of parent

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15
Q

What is the purpose of Mitosis?

A

Growth
Repair of damage (cuts)
Replace warn out cells

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16
Q

What is the purpose of Meiosis?

A

To produce gametes which are sperm and egg cells

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17
Q

In Meiosis, what makes it so that no sex cell is the same?

A

The process of independent assortment and crossing over. This is because these processes combine chromosomes into a mixture creating genetic diversity. So, every time its a different mixture. Even tho its one big pool of DNA it allows for a different mixture to be made each time.

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18
Q

What is the difference between anaphase 1 and anaphase 2 in meiosis?

A

Anaphase 1- splits the pair of chromosomes

Anaphase 2- splits the chromosomes into chromatids

19
Q

What is the difference between telophase 1 and telophase 2?

A

Telophase 1- replicated chromosomes, made of 2 chromatids

Telophase 2- unreplicated chromosomes, made of 1 chromatid

20
Q

Crossing over

A

The exchange of chromosome segments between homologous pairs during synapsis. Non-identical sister chromatids may exchange pieces of DNA and a chromatid may now be a mixture of maternal and paternal genes.

21
Q

What happens if a mistake is produced in a gamete in meiosis? Mitosis?

A

Meiosis- the mistake will be passed onto the zygote and will be continued in all its cells
Mitosis- the mistake is contained to one area

22
Q

Non-Disjunction

A

failure of chromosomes to separate properly in Meiosis. This results in a gamete that has too much info (2 copies of one chromosome) or too little(missing a copy of one chromosome)

23
Q

Why are division errors more common in older Woman?

A

Prolonged meiosis 1

24
Q

Karyotype

A

The chromosomes of an individual that have been sorted and arranged by their shape and type

25
Autosomes
Non sex-chromosomes
26
Trisomy (2n +1)
- 3 copies of a single chromosome (2 copies of all the rest) | - formed from a gamete with an extra chromosome (n+1)
27
Monosomy (2n -1)
- cell has only 1 copy of a single chromosome (2 copies of all others) - results from a gamete that is missing a chromosome (n-1)
28
Down Syndrome
a chromosomal abnormality in which an individual has 3 copies of chromosome 21 (AKA; trisomy 21)
29
Non disjunction disorders
1. Turner Syndrome- one x and no y sex chromosome 2. Klinefelter Syndrome- two x and one y sex chromosome 3. Patau Syndrome- trisomy of chromosome 13 4. Edwards Syndrome- trisomy of chromosome 18
30
Prenatal testing
Testing for a genetic order that occurs prior to birth | Common for mothers 35+
31
Tetrad
A pair of homologous chromosomes, each with 2 sister chromatids
32
Differences between Mitosis and Meiosis
Meiosis: - happens in germ cells - purpose is sexual reproduction - produces 4 new haploid daughter cells - chromosome number is halved in each daughter cell - genetic variation is increased Mitosis: - happens in somatic cells - purpose is cellular proliferation - produces 2 diploid daughter cells - Chromosome number stays the same - Genetic variation doesn’t change
33
Sexual Reproduction
when 2 parents (or cells) produce genetically diverse offspring
34
Fertilization
Fusion of sex cells to form a zygote e.g- sperm + Egg = Zygote 23 + 23 = 46
35
Somatic Cells
body cells. they contain 2 copies of every dingle chromosome or a diploid number (2n)
36
Homologous Chromosomes
chromosomes with the same genes are in the same loci, but may contain different forms (alleles). so they are similar, but not identical. in each pair, one chromosome is maternal and one is paternal in origin.
37
Sex Cells
Contain one copy of each chromosome, or a haploid # (n). Note: each sperm and egg cell contains 22 autosomes (chromosomes not directly involved in sex determination) a one sex chromosome either x or y *PRESENCE OF X MAKES A FEMALE PRESENCE OF Y MAKES A FEMALE
38
What is the purpose of making Sex chromosomes haploid?
by cutting them in half it makes it so they can pass on information to their offspring. E.G.- 1/2 info dad +1/2 info mom = 1 complete info
39
Key points for Mitosis
- Crucial; if your cells didn't divide you wouldn't grow (how does your body grow if your body cant make more cells?) - great for repair of damage; if you get a cut on your skin, you need meiosis to occur and produce more skin cells so you can heal - goal is to make IDENTICAL body cells; if you are trying to produce more skin cells to replace the warn out damaged ones you don't want to suddenly produce stomach cells.
40
Key points for Meiosis
* is a reduction division process* (46-23) - PMAT occurs TWICE
41
Stages in Mitosis
Interphase- where cell spends most of its life, DNA is replicated Prophase- crossing over occurs, cells pair up, chromatin shortens and thickens, nuclear membrane disintegrates Metaphase- chromosomes line up in the middle of cell, spindle fibers attach to centromeres. independent assortment occurs Anaphase- pair of chromosomes are split up and pulled to opposite sides of the cell Telophase- new nuclear membrane forms around each group of chromatins on each side of the cell, Cytokinesis- Cell splits and creates 2 daughter cells.
42
Stages in Meiosis
PMAT #1- same as Mitosis PMAT #2- prophase 11- nuclear membrane dissolves, spindle fibers begin to form Metaphase 11- chromosomes line up in the middle of the cell Anaphase 11- centromere splits chromosomes into chromatids and they each go to different sides Telophase 11- Cell divides and produces 4 haploid cells with unreplicated chromosomes
43
What needs to go wrong for an Aneuploid to result in | 2n +1) and (2n-1
in Meiosis 11, when the pair of chromosomes split into chromatids and the chromatids are not passed down to each daughter cell properly. so, 2 chromatids will go to one daughter cell and none will go to the other.

Biology (23 decks)

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