Exam 2 Flashcards
(103 cards)
1
Q
DNA
A
Located in the nucleus of eukaryotes
In loose strands the majority of the time
Condenses into chromosomes prior to division
2
Q
Centromere
A
Where sister chromatids (pairs) are attached and microtubules bind
3
Q
How many PAIRS of chromosomes are in your nucleus?
A
23 PAIRS
22 autosomal (homologous)
1 sex pair
4
Q
Mitosis
A
Exact copies of original cell
Everywhere but sex cells
Growth and repair of our bodies
5
Q
Interphase
A
Most time spent here
Loose DNA strands
DNA replicates (2 copies of each strand in nucleus)
6
Q
Mitosis
A
Prophase
Metaphase
Anaphase
Telophase
7
Q
Prophase
A
DNA condenses into chromosomes
Microtubules form anchored by centrioles
Nuclear envelope begins to break down
8
Q
Metaphase
A
Chromosomes align at the middle
9
Q
Anaphase
A
Pulling apart of the sister chromatid to opposite sides of the cell
(Both new cells will have same DNA)
10
Q
Telophase
A
Nuclear envelope reforms
Chromosomes unravel
11
Q
Cytokinesis
A
Splitting of one cell into two
12
Q
Pronto-oncogenes
A
Mitosis regulated by this
If they mutate, they no longer function properly, resulting in cancer
13
Q
Causes of cancer
A
Inherited mutations
(BRCA 1/BRCA 2=breast cancer)
Environmental carcinogens
(Smoking, UV radiation, HPV virus)
14
Q
Malignant
A
Tumor invades surrounding tissue
Cancerous
15
Q
Metastatic
A
Individual cells break off and start a new tumor elsewhere
Cancerous
16
Q
Benign
A
Tumor has no effect on surrounding tissue
Non cancerous
17
Q
Treating cancer
A
Surgery
Chemotherapy
Radiation
(Vaccines being developed)
18
Q
Meiosis
A
Cell division in sex cells
4 cells
Not identical to original
Half the DNA of the original
19
Q
Interphase (same as mitosis)
A
Copies of DNA
2 in each cell
20
Q
Prophase 1
A
Chromosomes and chromatid joins at centromere
**crossing over happens here-some chromatids (single strands) with have DNA from both mom and dad
21
Q
Metaphase 1
A
Homologous chromosomes pair up and randomly align in the middle of the cell
22
Q
Anaphase 1
A
Homologous chromosomes pulled towards the ends of the cell
**pairs here NOT just strands of DNA
23
Q
Telophase 1/Cytokinesis
A
Nuclear envelope reforms
Chromosomes unravel into loose strands
Cell splits
24
Q
Prophase 2
A
DNA condenses
**No crossing over this time
25
Metaphase 2
Chromosomes align in the middle of the cell
26
Anaphase 2
Sister chromatids are pulled pulled apart, splitting the pair
27
Telophase 2/Cytokinesis
Nuclear envelope reforms
Cell splits
**Haploid cells-only contain one copy of a chromosome (original cell was diploid with two copies)
Called gametes
28
Heterozygous
Two different alleles of a gene
29
Homozygous
Same allele of a gene
30
Dominant
One expressed in a heterozygote
31
Recessive
Not expressed in a heterozygote
| **expressed in a homozygote
32
Codominance
Both alleles expresses equally but separately
33
Incomplete dominance
Both alleles expressed but the phenotype is intermediate
34
Genotype
Genetic composition of an individual (ex. Bb)
35
Phenotype
The traits expressed by an individual (ex. Brown eyes)
36
Phenotypic plasticity
Same genotype, different phenotype
37
Phenotype is determined by:
Genotype AND environment
38
Mendel (1865)
Work with pea plants is the foundation for genetic inheritance
39
Mendel’s laws of inheritance
1. Segregation-alleles separate from each other during meiosis
2. Independent assortment-alleles of different genes are inherited independently of each other
3. Dominance-some alleles of a gene may be dominant over others
40
Dihybrid cross (both parent heterozygous at two genes)
(RrYy x RrYy)
Phenotypic ratio=9:3:3:1
**only possible is there is independent assortment of alleles from different genes
41
Genes on the same chromosome are often linked
Genes on DIFFERENT chromosomes aren’t linked
42
DNA replication
Occurs in interphase and inside the nucleus
43
DNA replication
Step 1: DNA double helix is unwound by he enzyme Helicase
| Step 2: DNA polymerase adds nucleotides complimentary to the original strand
44
DNA replication is semiconservative:
Resulting DNA double helices contain one original strand and one new strand
45
Mutations
DNA polymerase proofreader DNA strands during replication and fixes errors
Errors that don’t get fixed are mutations, that may result in new alleles of a gene
46
Sex chromosomes: what do they contain?
```
X & Y:
Genes for basic cellular function
Sex determination genes (SRY gene triggers male development)
X: ~800 protein coding genes
Y: ~70 protein coding genes
```
47
Recessive, disease causing alleles on the X chromosome are more harmful in males
XX-healthy
Xx-healthy carrier
xx-hemophilia
XY-healthy
xy-hemophilia
48
Only 1 X chromosome is “activated” per cell in females
Barr body is the inactivated X chromosome
49
Sex chromosomes cross over in the PAR regions: the ends
Both X to X and X to Y
50
Biological sex
Phenotype base in the combination of chromosomes, hormones, and sex organs
51
Gender
Personal and cultural identity pertaining to biological sex and other factors
52
Transgender
A person whose gender differs from the biological sex they were assigned at birth
53
Why might a person not identify with their assigned sex at birth?
CAH: inability to produce cortisol in XX, leading to masculinization
AIS: inability to produce or possess receptors for androgen in XY, leading to female phenotype
Klinefelter syndrome: individuals are XXY: May exhibit both male and female phenotypes
SRY gene crosses over onto the X chromosome
XXY, male sexual organs develop, male and female hormones
54
Sex determined by egg incubation temp in turtles and reptiles
Turtles
Male: low temp
Female: high temp
Crocodile
Male: high and low temp
Female: mid temp
55
Sequential hermaphroditism
Being able to change sex during the lifetime (clownfish)
56
Platypuses have 10 sex chromosomes
Males: XYXYXYXYXY
Females: XXXXXXXXXX
Similar to platypus autosome 6
57
Birds and butterflies have a ZW sex chromosome system
ZZ-male
| ZW-female
58
Honey bees
Diploid: females
Haploid: males (essentially unfertilized gametes)
59
Plants
Most are hermaphrodites: both parts on same plant
| Some are dioecious: parts on separate individuals (poison ivy and papaya)
60
Tetrahymena
Have seven different sexes
61
Why did separate sexes and sex chromosomes evoke?
Separate sexes prevents self fertilization and increases genetic diversity
62
How did sex chromosomes evolve?
Autosomes—->sex chromosomes
63
Transcription
Production of mRNA (AUGC)
64
Translation
Step 1: tRNA binds to specific amino acids depending on their RNA sequence
Step 2: rRNA moves across mRNA. tRNA antitoxins bind to mRNA codons, amino acids bind together
Step 3: ribosome reaches a stop codon on the mRNA, translation is finished
65
The genetic code is redundant (several codons code for one amino acid)
But it isn’t ambiguous (any particular codon codes for one specific amino acid)
66
GMO:
Organisms whose genome have been engineered, often incorporating genes from another organism
67
~80% of all processed foods contain at last one GMO
Corn, soybeans, cotton, potatoes, papayas, apples
68
Roundup ready soybeans:
Contain gene from bacteria, which confers resistance to the herbicide Roundup
69
Bt corn
Contains gene from bacteria, which produces toxin against the corn borer insect
70
Upsides of GMO crops
Produce more food
71
Potential downsides
$$
| Farmers can only use gmo’d seeds for one harvest
72
GMO medicines
GMO insulin-produced by yeast or bacteria, first GMO medicine
GMO blood clotting proteins (made by goats)
73
Gene therapy (GMO humans) vs CRISPR
Insertion of gene into harmless virus
| CRISPR much more specific than virus method
74
Stem cells
Undifferentiated cells that have not yet acquired a specific function
75
Brain stem
Governs reflexes and spontaneous functions
- midbrain: adjusts sensitivity of the eyes and ears
- pons/medulla oblongata: relay messages between spinal cord and brain
76
Cerebellum
Balance, coordination, muscle memory
77
Thalamus
Relay center for sensory signals except smell
| Amplifies or suppresses signals before they go to cerebrum
78
Limbic system
Hypothalamus
Amygdala
Hippocampus
79
Hypothalamus
Control center for temperature regulation, blood pressure, thirst, sex drive, emotion
Hormone production
Pituitary gland
80
Amygdala
Fear, pleasure, emotional response
| Flight/flight
81
Hippocampus
Learning
| Short term memory
82
Cerebrum
Planning, creativity, consciousness, voluntary movement, language
83
Four lobes
Frontal-higher thinking
Parietal-touch
Occipital-visual information
Temporal-auditory information
84
Brain hemispheres
Control the opposite sides of the body
85
Corpus callosum
Connects the hemispheres
86
Cerebrospinal fluid
Cushions and protects the bran from the skull
87
Concussions
Cause shock, headache, confusion
| Can cause irritability, trouble sleeping, depression, brain damage
88
Woodpecker traits that reduce concussions
Less cerebrospinal fluid
Spongy bone layer and hard, elastic bone layer (to absorb impact)
Can get brain damage
89
Brain compared to other species
| Common wormlike ancestor ~600 million years ago
Human brain-cerebrum wrinkled (increases surface area)
Mouse brain-cerebrum smooth
Dolphin brain-memory, play/experiment, cooperation/problem solving
Bird brain-small, smooth (although highly intelligent), problem solving, memory
Octopus brain-majority of neurons in arms, not the brain, short and long term memory, recognize individuals, no common brain anatomy, independent evolution of a complex brain
90
Central nervous system
Brain and spinal cord
91
Peripheral nervous system
Nerves radiating through the rest of the body
92
Neurons
Specialized cells that carry messages in the brain and nervous system
93
Sensory neurons
Carry information from the body to the CNS
94
Motor neurons
Carry information AWAY from the CNS towards the rest of the body
95
Anatomy of a neuron
```
Dendrites
Cell body
Axon
Terminal boutons
(Nerves are bundles of axons)
```
96
How do signals move through a neuron?
Begins at dendrites travels through cell body and axon to terminal bouton
Action potential travels down the axon
Normal charge restored behind action potential
97
How does a nerve impulse travel from one neuron to the next?
Synapse: a junction between two neurons
98
Neurotransmitters
Transmit the signal between neurons at the synapse
99
Removal of neurotransmitters from synapse
Reuptake into pre-synaptic neuron through channel OR digestion by enzymes in the synapse
100
Rene Descartes
Mathematician
Proponent of rational thinking regarding the natural world
Believed that the pineal gland contains the human soul
101
Phrenology
Pseudoscience claiming the shape and size of the skull indicates a person’s personality and abilities
102
Phrenology and the Rwandan genocide
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Belgian colonizers (1930s) claimed Tutsis were more “European” than Hutus, and therefore superior
In 94 between 500,000 and a million people were killed within 100 days
```
103
Sea slugs and the human mind
Sea slugs have large neurons
Molecular basis of learning and memory
Short term memory involves changes in existing synapses, while long term memory builds new synaptic connections
