semester 2 final review Flashcards
What is the difference between prokaryotes and eukaryotes?
- prokaryotes - no nucleus or membrane-bound organelles, circular DNA - bacteria
- eukaryotes - nucleus and membrane-bound organelles, linear DNA, every organism except bacteria
the control center of a cell, contains genetic code (DNA)
nucleus
What are the 2 forms of DNA?
chromatin - uncoiled - not dividing
chromosomes - tightly coiled, dividing
the organelle that breaks down old, worn out organelles and food
lysosome
the site of protein synthesis
ribosome
the path of proteins in a cell
ribosome - ER - Golgi
the organelle that converts food into usable energy for cells
mitochondrion
organelles found in plant cells but not animal cells
chloroplasts
What is the difference between a cell wall and a cell membrane?
- cell membrane - selectively permeable
2. cell wall - rigid structure for support only
cell’s boundary from its environment
cell membrane - lipid bilayer
What causes diffusion?
particles have KE and are always in motion and colliding with one another so they tend to spread out from high to low concentration
What type of particle transport requires energy?
active transport
The type of particle transport where a cell surrounds and engulfs material to bring it into a cell
endocytosis
Where is the energy stored in ATP, and how is that energy released?
in phosphate bonds - break off a phosphate
What do we call producers that make food by photosynthesis and chemosynthesis?
autotrophs
What is the equation for photosynthesis?
CO2 plus H20 yields carbohydrates and O2
What is the equation for respiration?
carbohydrates (C6H12O6) plus O2 yields H2O plus CO2
What does the word aerobic mean?
with oxygen
What organelle is where photosynthesis occurs?
respiration?
photosynthesis - chloroplasts
respiration - mitochondria
How are photosynthesis and respiration?
The reactants of one are the products of the other.
What are the two halves of a chromosome called, and what holds them together?
sister chromatids are held together by a centromere
During what phase of the cell cycle do the chromosomes line up along the middle of the cell?
metaphase
What are the stages of mitosis in order?
prophase, metaphase, anaphase, telophase
What is the role of the spindle fibers in mitosis
help separate the chromosomes
What is a difference in cell division of plant and animal cells?
Plant cells have a cell plate while animal cells pinch in.
What happens in cancer?
Cells can’t control their growth rate.
What do we call a mass of cancer cells?
tumor
How many alleles do gametes contain for each trait?
Gametes have 1 allele for each trait.
What is a mule called because it is the product of a horse and donkey?
hybrid
A heterozygous tall pea plant is crossed with a short plant. What is the probability of a tall plant?
50%
Organisms with 2 identical alleles for a trait are called what?
homozygous
If an organism’s diploid number is 12, what is its haploid number?
6
What process makes gametes?
meiosis
What are the cells like formed by meiosis?
4 genetically unique cells
What stores information in a cell?
DNA
What are nucleotides made up of?
deoxyribose, phosphate and a base, either A, T, G, or C
If one side of DNA is CTA, what is the other side?
GAT
What sugar is in RNA?
ribose
What bases are in RNA?
A, U, G, C - no thymine instead uracil
What type of RNA brings the code out to make proteins?
messenger RNA
How many types of RNA are there?
3
How many nucleotides does it take to code for 3 amino acids?
9
Genes have information for assembling what?
protein
What is the result of most mutations?
no effect
How many chromosomes are in a normal human karyotype?
46
Why is colorblindness more common in males?
sex-linked on X chromosome and recessive
What is a Barr body?
an inactivated X chromosome in a cell
Has any baby every been born without an X chromosome? Explain.
No - too many important genes are on the X
What type of breeding is more likely to bring 2 recessive genes together and cause a defect?
`inbreeding
How does DNA fingerprinting work?
No 2 people other than identical twins have the exact same DNA
According to natural selection, what organisms survive?
the ones most suited to their environment
What do all organisms have in common?
They all have DNA as their genetic information.
When a farmer chooses the best dairy cows to breed for future generations, what breeding technique is being used?
selective breeding
Most fossils are found where?
sedimentary rock
What does the theory of endosymbiosis say?
eukaryotes came from mutualistic prokaryotes living inside other prokaryotes - mitochondria were able to metabolize oxygen
How does sexual reproduction give variety?
mixes the DNA of 2 organisms
What do we call organisms that break down other organisms?
decomposers
How can we evaluate the relatedness of 2 organisms?
similarity in DNA
How are ATP and ADP related?
ATP has 3 phosphates while ADP has 2
What lets the plants absorb light?
pigment called chlorophyll
Why are plants green?
Chlorophyll reflects green and absorbs everything else
Why would a candle in a jar with a plant burn longer than one without a plant?
The plant makes oxygen which is needed to burn.
What would happen to photosynthesis with no carbon dioxide?
It would stop completely.
What happens to photosynthesis as light intensity increases?
It increases and then levels off.
What reactions (photosynthesis and respiration) are in plants? in animals?
plants - both
animals - respiration oly
What happens to chromosomes during cell division?
replicated (copied) and then divided evenly so new cells have a full set
Why are stem cells important?
have the potential to become other cell types
In what cells is the accurate transmission of information most important?
sex cells - They make the original cell.
Compare and contrast mitosis and meiosis.
mitosis - makes 2 identical cells, produces all cells except egg and sperm
meiosis - makes 4 haploid and unique cells, only makes eggs and sperm
Compare and contrast DNA and RNA.
DNA - deoxyribose, ATGC, double strand, stays in nucleus, genetic code, only 1 form a double helix with hydrogen bonds holding base pairs together
RNA - ribose, AUGC, single strand, can leave nucleus, reads code and builds protein, 3 different forms (mRNA, tRNA and rRNA), no base pairing
What is our evidence for evolution?
- We have an extensive fossil record with more simple things found from longer ago.
- Organisms are well suited to their environment, and we can trace changes in the genes that are responsible for those traits.
- All organisms have DNA as their genetic code, and we know that DNA sometimes mutates as it is passed from parents to offspring and that those mutations can occasionally help an organism survive or make them less likely to survive.
- The driving force behind evolution is a changing environment. Organisms compete for survival and either adapt or go extinct.
- Organisms that are well suited for their environment don’t need to change while organisms that aren’t suited need to adapt and change more. Sponges are relatively unchanged because they are so well suited.
