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bio - midterm 2 > things from the review > Flashcards

things from the review Flashcards

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Biology 101 flashcards
1
Q

DNA structure

A
  • double helix/staircase
  • made up of 2 nucleotide polymers (2 DNA strands together)
  • strands are held together by hydrogen bonds between base pairs
  • adenine/thymine and cytosine/guanine
  • differences in DNA sequence can result in genetic variation between individuals
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2
Q

where does DNA replication occur?

A
  • during S phase of cell cycle
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3
Q

DNA replication steps

A
  • hydrogen bonds are broken and the parent DNA strands separate
  • DNA polymerase attaches to the parent strand to build the new daughter strand by adding together nucleotides which compliment the sequence of the parent strand
  • two final DNA strands are half new and half old (parent and daughter strand)
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4
Q

replication errors

A
  • errors are normally 1 in 10,000 nucleotides
  • DNA polymerase can proofread to reduce error rate to 1 in 10 million
  • can result in mismatch error if not corrected
  • mismatch repair enzymes - correct mismatches when they occur
  • mismatch errors result in mutations - changes in part of DNA sequence that encodes a gene
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5
Q

replication errors steps?

A
  • polymerase adds incorrect nucleotide to new DNA strand
  • polymerase detects that bases are mispaired
  • polymerase uses exonucleus activity to remove incorrect nucleotides
  • DNA strand is cut and mispaired nucleotides and neighbours are removed
  • missing patch replaced with correct one
  • DNA ligase seals gap
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6
Q

DNA structure

A
  • RNA is made through transcription
  • single stranded nucleotides held together by covalent bonds
  • RNA = uses ribose sugars
  • segments of DNA code for RNA
  • RNA molecules encode for proteins
  • DNA -> RNA -> proteins
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7
Q

3 types of RNA

A

mRNA - carries genetic info from the DNA in the nucleus to ribosomes, the sites of protein translation in cytoplasm
rRNA - ribosomes are composed of rRNA and protein. ribosome is key regulator of translation, they “read” the code carried by mRNA
-tRNA - molecules of tRNA bring specific amino acids to ribosomes, where they are linked to form proteins

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8
Q

transcription definition

A
  • produce mRNA from DNA gene sequence
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9
Q

transcription steps

A
  1. RNA polymerase - binds to open DNA strand
  2. RNA polymerase - links together RNA bases complimentary to those of the DNA strand to make one single stranded RNA molecule
    - begins when RNA polymerase binds to promotor region in DNA, and ends at terminator sequence
    - RNA moves from nucleus to cytoplasm
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10
Q

translation definition

A
  • assembles amino acid sequence of proteins in particular order based on the mRNA sequence
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11
Q

codon

A
  • sequence of 3 nucleotides in mRNA sequence which specifies 1 amino acid
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12
Q

translation steps

A
  • ribosomes are made of rRNA and proteins.
  • they read the mRNA sequence and link amino acids together according to codon sequence
  • tRNA- brings amino acids to mRNA and ribosomes
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13
Q

genes

A

-segment of DNA within chromosome serving as codes for proteins
- proteins made through transcription and translation
- basic unit of inheritance

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14
Q

alleles

A
  • alternative version of type of gene
  • produces genetic variation
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15
Q

genotype

A
  • genetic makeup of an organism (present alleles)
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16
Q

phenotype

A
  • observable physical characteristics (eye colour)
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17
Q

dominant allele

A
  • determines the phenotype (A)
18
Q

recessive allele

A
  • repressed by dominant allele (a)
19
Q

homozygote

A
  • an individual that contains two of the same copies of an allele (AA)
20
Q

heterozygote

A
  • an individual that contains two copies of an allele (Aa)
21
Q

Mendel’s theory of inheritance

A
  1. alleles cause variation in inherited traits
  2. offspring inherit one copy go a gene from each parents
  3. an allele is dominant if it has exclusive control over the phenotype when pair with another allele
  4. the two alleles of a gene segregate during meiosis and end up in different gametes
  5. gametes fuse without regard to which allele they carry
22
Q

law of equal segregation

A
  • parental genes must separate randomly and equally into gametes during meiosis so there is an equal chance of the offspring inheriting either allele
  • one homologous chromosome for each cell
  • individuals possess 2 alleles, one form each parent when gametes fuse
23
Q

law of independent assortment

A
  • inheriting an allele has nothing to do with inheriting an allele for any other trait
  • alleles from parents are passed on independently to the offspring and after fertilization, the resulting zygote can end up with any combination of chromosomes from the parents
  • all the possible combinations occur with equal frequency
24
Q

incomplete dominance

A
  • a heterozygotę phenotype is an intermediate between two homozygotes
  • resembles “blending inheritance theory”
  • neither red nor white is either dominant or recessive - its a mixture of both
25
Q

polygenic traits

A
  • in most characters/traits, they are controlled by multiple genes and not just one
  • skin colour is controlled by 3 genes have have equal influence
26
Q

multicellularity and specialization challenges

A
  • continuous development: after reproduction, organisms must undergo development
  • transport system: need to move materials to sometimes distant cells
  • communication: cells needs to communicate to coordinate activity with other cells
27
Q

multicellularity and specialization challenges response and advantage

A
  • cell specialization
  • cells perform few functions, but are focused solely on that function
  • specialized cells can’t survive as individuals
  • ADVANTAGE - multicellular organisms have more control of environment in which cells reside
28
Q

epithelial cells

A
  • form surfaces and line body cavities
29
Q

connective cells

A
  • produce matrices that connect and support different tissues found in various organs (blood, tendons, bone and fat)
30
Q

muscle cells

A
  • contract and relax to give animals ability to move (cardiac, skeletal and smooth muscle)
31
Q

nerve cells

A
  • transmit nerve signals throughout the body
32
Q

3 types of skeleton

A
  • endoskeleton - bones inside human hand
  • exoskeleton - shell outside a snail
  • hydrostatic - water pressure inside earthworm
33
Q

skeleton

A
  • connections of bones and cartilage that give support and shape to an organisms
34
Q

bone tissue

A
  • connective cells surrounded by collagen and a calcium matrix
35
Q

bone, calcium and collagen

A

bone - calcium embedded in collagen matrix
- calcium - mineral that provides rigidity and strength
collagen - proteins that provides resistance to tension (reduces brittleness and produced by connective cells called osteocytes)

36
Q

marrow

A
  • source of blood cells and other proteins
37
Q

bone remodelling

A
  • requires calcium for this to happen (requirement for adults is 1000mg/day)
  • remodelling is changing the thickness of bone
  • occurs in response to exercise and hormones
38
Q

components of the skeleton (3)

A
  • cartilage - cells that produce collagen and supports and supplements bones
    ligaments - flexible sheets of tissues and join bone to bone
    hydrostatic skeleton - uses fluid pressure to become rigid
39
Q

knee joints

A
  • joints - breaks in the skeletal system
  • skeletons without joints have limited movement
  • ligaments - connect bone to bone
  • tendons - connect bone to muscle
  • cartilage disc - cushion the impact on knees
  • synovial sacs - lubricate knee joint with fluid
40
Q

injury to the knee - osteoarthritis

A
  • progressive degenerative condition that wears down cartilage
41
Q

injury to the knee - ACL tear

A
  • when the femur (thigh) twists one way and the tibia/fibula (calve) twists another resulting in torn ligament
  • causes torsion on ligaments in knee and under high pressure, ligament will snap

bio - midterm 2 (4 decks)

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