Genetics Quiz 1 Flashcards
(23 cards)
What is Interphase?
- Marked by a period of rapid growth, the replication of chromosomes, another period of growth, and preparation for future divisions (G1, S, G2)
- Each single strand off DNA (chromatid) duplicates and becomes double-stranded
Each double-stranded pair is attached at the centromere, and are known as sister chromatids
[Mitosis] Explain what occurs in Prophase.
- Chromosomes shorten and thicken (condense)
- Centrioles move to opposite poles (they provide attachment for spindle fibers)
- Nucleus disappears
[Mitosis] Explain what occurs in Metaphase.
- Sister chromatids line up at the equator of the cell
[Mitosis] Explain what occurs in Anaphase.
- Centromere divides and chromosomes move to opposite ends of the cell
[Mitosis] Explain what occurs in Telophase.
- Chromosomes reach opposite ends of the cell, begin to lengthen, and a nucleur membrane begins to form around them
- Spindle fibers dissolve
- Cytokinesis (division of cytoplasm) occurs
(1) Define key terms: STRUCTURE, DIPLOID (2N), HAPLOID (N), DNA, MITOSIS, MEIOSIS
- STRUCTURE: refers to any pattern in the genetic makeup
- DIPLOID (2N): cells with paired sets of chromosomes that carry the same information
- HAPLOID (N): cells that do not have pairs of chromosomes (sex cells)
- DNA: the molecule that carries genetic information for the development and functioning of an organism
- MITOSIS: a process of cell duplication, or reproduction, during which one cell gives rise to two genetically identical daughter cells
- MEIOSIS: the process that produces haploid sex cells
(2) Define key terms: CHROMATIDS, CHROMOSOMES, ALLELE, SISTER CHROMATIDS, CENTROMERE, HOMOLOGUS CHROMOSOMES
- CHROMATIDS: one of the two strands of a chromosome that has been duplicated/copied during cell division
- CHROMOSOMES: microscopic threadlike part of a cell that carries hereditary information in the form of genes
- ALLELE: a variation of a gene
- SISTER CHROMATIDS: two identical copies of a single chromosome that are connected by a centromere
- CENTROMERE: the region of a chromosome where the spindle fibers attach
- HOMOLOGUS CHROMOSOMES: not identical, but similar
(3) Define key terms: GAMETOGENESIS, SPERMATOGENESIS, OOGENESIS, TELOMERE, TETRAD, NUCLEOTIDE
- GAMETOGENESIS: a biological process by which gametes (sex cells) are produced
- SPERMATOGENESIS: the biological process of producing sperm cells
- OOGENESIS: the process of the development of female gametes (ova or eggs)
- TELOMERE: on the ends of chromosomes, makes sure chromosomes don’t stick together
- TETRAD: 2 homologous chromosomes that replicated into a pair of sister chromatids
- NUCLEOTIDES: organic molecules composed of a nitrogenous base, a pentose sugar and a phosphate.
[Meiosis] Explain what occurs in Prophase I.
- DNA copied
- Nucleus disappears
- Spindle fibers form
- When the tetrads form and connect to each other ‘synapsis’ occurs (homologous pairs align with each other)
- ‘Crossing over’ occurs (chromatids intertwine)
- Genetic shuffling occurs, and it’s random
[Meiosis] Explain what occurs in Metaphase I.
- Chromosome pairs are aligned randomly
- Genetic shuffling occurs
[Meiosis] Explain what occurs in Anaphase I.
- Unique chromosomes, sides are genetically different
[Meiosis] Explain what occurs in Telophase I.
- Information of mom and dad is here, but its PARTS of mom and PARTS of dad > not the full information
- Nucleur membrane forms temporarily
[Meiosis] Explain what occurs in Prophase II.
- Duplication does NOT occur here
- No ‘crossing over’ occurs here
[Meiosis] Explain what occurs in Metaphase II.
- Chromosomes line up (random alignment)
- Genetic shuffling occurs
[Meiosis] Explain what occurs in Anaphase II.
- Chromatids are split up
- They go to opposite poles
[Meiosis] Explain what occurs in Telophase II.
[No pairs, but separate chromatids]
- Will be split
- Each cell is unique
- Nucleur membrane reforms (only has HALF the genetic information)
What are the 4 types of mutations? Explain how it occurs.
- Insertion > another nitrogenous base is added and everything is shifted over
- Deletion > when one or two nitrogenous bases are removed
- Inversion > when nitrogenous bases get inverted (last ‘word’ becomes first)
- Translocation > location of the nitrogenous bases are moved
Describe the structure of DNA and its polymers (ex: nucleotides)
- Made up of sugars (deoxyribose), phosphate, and 4 nitrogenous bases: adenine [A], guanine [G], cytosine [C], and thymine [T]
- Each molecule of DNA is a double helix formed from two complementary strands of nucleotides held together by hydrogen bonds between G-C and A-T base pairs
- Sugar and phosphate molecules form backbone (“of ladder”) while nitrogenous bases form rungs
Which nitrogenous bases are purines and which are pyrimidines?
- PURINES: adenine and guanine, they are comprised of 2 rings
- PYRIMIDINES: cytosine and thymine, they are comprised of 3 rings
How do you determine the complimentary sequence of nucleotides if given a DNA strand?
- A > T
- G > C
- When needed to know the amount of rings: use the n’s in purine (2n = 2 rings) and the n in pyrimidine (n = 1 ring), then add
What is the “formula” to determine the number of chromosomes/chromosome pairs at each stage of meiosis?
- What ever the specified amount is x2
- ## The OG specified amount
- OG specified amount of pairs is now the single chromosomes and there are NO pairs
Explain the process of spermatogenesis in biological males.
- Equal division of cytoplasm with sperm
- 4 cells produced via meiosis - — Diploid spermatocytes give rise to sperm cells
- Capable of many mitotic divisions before meiosis
- Up to 1 billion sperm cells produced per day
Explain the process of oogenesis in biological females.
- Cytoplasm of female gametes doesn’t divide equally after nuclear division
- One daughter cell ootid receives most of cytoplasm then use the nutrients and organelles to fuel future cell divisions in the event the egg is fertilized
- Therefore, only one ovum (egg cell) is produced
- The other 3 polar bodies die and the body absorbs the nutrients.
- Baby females are born with ~ 2 million primary oocytes (already entered meiosis I and remain suspended in prophase I until puberty) in ovaries
- Most are absorbed into body
- About 300,000 oocytes remain
- 400-500 released during reproductive years
