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Biology Grade 11U > Unit 3 > Flashcards

Unit 3 Flashcards

(57 cards)

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1
Q

What are nucleotide made of?

A

A sugar- phosphate backbone and a nitrogenous base (A, T, G, C)

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2
Q

What are the nitrogenous base pairings?

A

Adenine matches with Thymine
Guanine matches with Cytosine

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3
Q

Who created the structural model of DNA?

A

James Watson and Francis Crick in 1952

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4
Q

What are histones?

A

Histones are the proteins wounded around DNA.

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5
Q

What is the importance of the base pairing in DNA?

A

The base pairing in DNA makes up the genetic code of an organism (genome is our whole genetic code).

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6
Q

What are Karyotypes?

A

A persons particular arrangement of chromosomes. Chromosomes can range in side (humans have 23 pairs and 46 in total)

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7
Q

What are autosomal chromosomes?

A

Regular chromosomes are autosomal (humans have 22 pairs of autosomal)

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8
Q

What are sex chromosomes?

A

Sex chromosomes tell the sex of the organism and is placed last in the chromosome picture line-up (XX for female, XY for male)

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9
Q

How do cells use DNA?

A

All DNA in the body has the same DNA but uses only a part of the DNA to do their job.

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10
Q

What is Asexual reproduction?

A

Asexual reproduction is done from a single-celled parent by cell division (mitosis). Offspring is genetically identical to parent

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11
Q

Advantages of asexual reproduction?

A
  • Parents organisms do not need to seek out a mate to reproduce
  • Specialized mating behaviours are not needed
  • No specialized anatomy
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12
Q

What is Budding?

A

When an offspring develops from outside of the parent organism. When their offspring grows large enough, it detaches and lives on its own. Ex. Hydra

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13
Q

What is Fragmentation?

A

A piece of the parent organism breaks off and matures into its own. Ex. mushrooms grow spores that develop into mushrooms

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14
Q

What is the cell cycle?

A

The cells cycle of life. Starts in the growth stage (Interphase) then the division stage which is much shorter and split into to parts: Mitosis (prophase, metaphase, anaphase, and telophase) and cytokinesis.

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15
Q

What happens in Prophase?

A
  • Chromatin (DNA) condenses into
    chromosomes
  • Centrioles move to opposite ends of the cell
  • Spindle fibers form from the centrioles
  • Nuclear membrane dissolves
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16
Q

What happens in Metaphase?

A
  • Spindle fibers attach to centromeres
  • Chromosomes align along the equatorial plate
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17
Q

What happens in Anaphase?

A
  • Spindle fibers shorten
  • Centromere splits and pulls chromatids to opposite ends of the cell
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18
Q

What happens in Telophase?

A
  • Chromosomes relax into chromatin
  • Nuclear membrane reappears
  • Two new nuclei are formed
  • Spindle fibers disappear
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19
Q

What happens in Cytokinesis?

A
  • the cytoplasm divides
  • In animal cells, cleavage furrows are formed
  • In plant cells, cell plates are formed
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20
Q

Disadvantages of sexual reproduction?

A
  • Specialized organs are needed to produce the sex cells
  • Need courtship techniques to mate like bright colours but that could also attract predators
  • May require the lost of a resource such as nectar in flowers
  • The offspring may be weak or unable to survive when combining the genetic information
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21
Q

Advantages of sexual reproduction?

A
  • Allows for evolution due to the genetic variability
  • Can support the long term survival of a species
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22
Q

What is sexual reproduction?

A

Sexual reproduction is the fusion of 2 sex cells which makes a genetically unique offspring. This is done in 2 steps:
- The 2 sex cells joining to form a zygote, the first cell of a genetically unique individual through fertilization
- The formation of a haploid cell or gamete which contains genetic information from both parents

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23
Q

What are some modes of sexual reproduction with examples?

Study These Flashcards
A
  • External fertilization: parrot fish have egg cells that are layed and sperm cells fall on it
  • Internal fertilization: Humans (most mammals)
24
Q

How many chromosomes is in the cell during Meiosis 1 Prophase 1?

Study These Flashcards
A
  1. Diploid cell containing 23 pairs of homologous chromosomes
25
What is meiosis?
A special type of cell division similar to mitosis. Present in organism that sexually reproduce and is the process that makes the gametes (sperm and egg cells) for sexual reproduction.
26
Difference between Mitosis and Meiosis?
- Mitosis has the same number of chromosomes in each generation (from parent cell to daughter cell) - Meiosis starts with a diploid cell and ends with 4 haploid cells (chromosomes reduce by half by the end)
27
How does genetic variation occur in Meiosis
- The combination of two gamete cells each containing a complete set of DNA (one from each parent which contains one version of each gene) creating homologous chromosomes - Genetic variation occurs during prophase 1 when homologous pairs crossover - In metaphase 1 and 2 when chromosomes randomly pick which side to go to
28
Recite Meiosis for human sperm and egg cells
29
What is the production of sex cells?
The production of sex cells is called gametogenesis whcih is done through meiosis. In humans there are 2 types: spermatogenesis (1 diploid cell to 4 sperm cells) and oogenesis (1 diploid cell to 1 ovum and 3 polar bodies).
30
What term describes the improper chromosome separation in meiosis?
Nondisjunction
31
What term describes the process of traits being passed from parent to offspring?
Heredity
32
What is the chemical composition of DNA?
Discovered by Phoebus Levene, DNA is made of a pentose sugar (5 carbon sugars), a phosphate group, and a nitrogenous base. All together this is a nucleotide.
33
What are the 2 types of nitrogenous bases?
Pyrimdines (cytosine, thymine) and Purines (guanine and adenine)
34
What happens when a sequence of nucleotides is translated by the ribosome?
The sequence of nucleotides will produce a certain protein when going through the ribosome. 3 nucleotides is called a codon.
35
What is the key relationship between nitrogenous bases?
Erwin Chargaff discovered that the amount of Adenine is equal to the amount of thymine and the amount of guanine is equal to the amount of cytosine.
36
What is multiple births?
More than one egg can get released and fertilized separately (leading to fraternal twins) or the zygote splits early and becomes two cells (identical twins).
37
What is independent assortment in meiosis?
During Metaphase 1, the homologous chromosome pairs are randomly oriented when lining up at the poles.
38
What is crossing over in meiosis?
During prophase 1, genetic material is exchanged between maternal and paternal chromosomes in multiple sections. However, errors can occur causing errors in the chromosome sequence.
39
What are errors in chromosome number?
Euploidy: when a human has the correct number of chromosomes Aneuploidy: when a person has the wrong amount of chromosomes (resulting in non-disjusction in meiosis) Monosomy: chromosome missing Polysomy: additional chromosome
40
Effects of non-disjunction in anaphase 1 and 2?
When non-disjunction happens during anaphase 1, no normal gametes will be created. If in anaphase 2, half the gametes will have the correct chromosome number. IF the gamete with an abnormal chromosome number undergoes successful fertilization, that resulting individual will have an extra or missing chromosome.
41
Disadvantages of errors in meiosis?
Have a dramatic impact on the development and survival of their offspring. In humans it can result in genetic disorders like down syndrome (polysomy) and Cri du Chat (deletion of chromosome 5). In both animals and plants with aneuploidy, they are infertile
42
Errors in Chromosome Sequence?
- Deletion: loss of chromosomal segment (example: cri du chat) - Duplication: repeated segment (chromosome 1 gives x to chromosome 2 but chromosome 2 keeps their x so now it has 2) (example charcot-marie-tooth disease) - Inversion: reversed segment (after separating, the chromosome changes the sequence of the alleles) (example FG syndrome) - Translocation: 2 chromosomes that are not homologous pairs form a tetrad and switch alleles that shouldn't be switched (aren't from the same chromosome number) (example chronic myelogenous leukemia)
43
Examples of chromosome abnormalities in humans?
- Trisomy 21 (extra chromosome 21 causing down syndrome, effects: intellectual disabilities, short stature) - XO Turner syndrome ( missing an X chromosome causing sterile females, can't produce eggs, underdeveloped female characteristics) - Trisomy 18 Edward syndrome (life expectancy about 10 weeks, severe adnormalities)
44
What is aminocentesis?
A prenatal test that allows your healthcare practitioner to gather information about your baby's health from a sample of your amniotic fluid- this is the fluid that surrounds your baby in the uterus
45
What are problems with Fertillization?
- Problems with fertilization are more common than chromosomal abnormalities - Causes include: poor or reduced egg or sperm quality/quantity
46
What is mutation and what causes it to occur?
Mutations are mistakes during cell division. Spontaneous mutations are mutations that happen naturally on accidents and can be the result of incorrect copying of DNA. Induced mutations happen when exposed to a physical or chemical agent like UV radiation, cigarette smoke, chemicals in processed foods, etc.
47
What are point mutations?
A point mutation is a failure in replicating cells to copy the genetic information accurately causing base-pair substitution, insertion, or deletion
48
What are chromosome mutations?
Chromosome mutation involves a mutation of an entire chromosome or a large part of it. Nondisjunction is an example of chromosome mutation happening in meiosis which can result in genetic disorders if it happens in gametogenesis or early in development during mitosis.
49
How are mutations inherited?
Mutations that occur in somatic cells are not passed onto offspring so it does not affect future generations. However, mutations that occur in the formation of sex cells become part of the DNA of the zygote. This means the offspring will have a copy of every cell of its body, including its sex cells, so it will pass it on to future generations.
50
Example of inherited mutations?
- Lactose Intolerance: A common trait in which people are not able to digest lactose (common sugar in milk). Caused by a deficiency of the lactase enzyme. When consuming a lot of dairy products, the undigested lactose will metabolize by intestinal bacteria which causes bloating, cramping, and diarrhea - Sickle-cell anemia: Both helpful and harmful caused by a single amino acid substitution making red blood cells into c shaped and less effective at moving oxygen around the body via blood. Increases risk of infection however, the parasite malaria, cannot survive in people with sickle-cell anemia since the cells aren’t doing their job, they are destroyed along with the malaria parasite
51
What is complete dominance?
When one allele is expressed in the phenotype even when there is another allele present. Basically, the dominant allele is expressed even if the genotype is heterozygous.
52
What is incomplete dominance?
When 2 alleles interact with one another and instead of one being dominant, they blend
53
What is codominance?
Both alleles mask each other and show up mixed in the phenotype, Example: shorthorn cattle
54
Codominances and dominance in blood types?
Blood types are inherited from 3 possible alleles: I^A, I^B, and i. Each of the alleles code for a different enzyme that places different sugars in the red blood cells surface. This indicates that I^A and I^B alleles are co-dominant to each other (they both show up on the red blood cell) However, I^A and I^B are completely dominant to i allele.
55
56
What is codominance?
When the 2 traits show up together in the phenotype.
57

Biology Grade 11U (3 decks)

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