Lec. 6 Leaves, Fruits, Seeds Or Animals? Flashcards
What are cotyledons?
primordial leaves preformed in the seed.
What happens to your body if you
1. eat raw beans,
2. raw castor beans
or 3. raw corn?
- Raw beans: makes you sick
, 2. Raw castor beans: can kill you,
3 raw corn: nothing
Name two key differences between plant seeds and mammal babies.
Developing seeds have no access to nutrients provided by their mothers. Seeds can remain dormant in the ground until they sprout and start growing.
Give an example of a plant that produces an ocean-going seed that transports
its own water.
Coconut
What happens to the fat inside a coconut when the seed germinates?.
it is transformed in sugar so the the growing palm can make cellulose.
How is it possible that Strychnos is an edible fruit if the plant is the source of
strychnine?
The toxin is in the seeds, not in the sweet fruits flesh.
What is coprophagy?
the eating of feces.
What is the different between a pollen grain and a seed?
The pollen grain contains the male gametes (two sperm) and the seed contains a plant embryo (plus nutrients).
Give an example each of a plant each, that has a pattern of flowering that is
bisexual, monoecious=separate male and female flowers on same plant, and dioecius=male and female flowers on separate plants.
tomato, cucumber, date palm
What does double fertilization in flowering plants refer to?
the fact that one sperm in the pollen tube fertilizes the ovule (egg cell) and the other fuses with a diploid cell to form the seed nutrients (endosperm).
Give two examples of plants that have separate male and female plants:
Date palms and Kiwi.
Give three examples of important crops that are propagated asexually.
banana, taro and cassava.
What is the distinguishing feature of monocot plants versus dicot plants?
Monocots sprout a single, dicots two leaves
List five of each, monocot and dicot crops:
Monocots:
onion,
corn,
coconut,
garlic,
turmeric
Dicots:
beans
spinach
cabbage,
passion fruit,
avocado
Which plant was domesticated first, the apple or wheat?
wheat
What is the meaning of polyploidy?
multiple copies of chromosomes in the genome.
Why would farmers repeatedly have bred plants into polyploid varieties?
bigger plants, seeds and fruit.
How can one prepare DNA from living cells?
- Detergent, water and salt mixed to lyse the cells (lipid rich membranes of the cell and the nucleus dissolve);
- Straining away the rough parts;
- Adding cold rubbing alcohol to precipitate the DNA from the soap salt water solution into white slimy goop.
Which large animals used to disperse avocado seeds in Central America?
extinct elephant relatives
What are the four classes of major biomolecules?
Nucleic Acids, Proteins, Glycans, Lipids.
Which two classes of biomolecules are not directly encoded in the genome?
Glycans and Lipids.
If one of your cells were 1000 times bigger than real life, how long would the genome (haploid) be?
~1km (~1000 yards)
How big is a human egg cell?
about the size of a grain of salt (e.g. Norton table salt).
How does all the DNA fit into the nucleus of a cell?
What is the study of chromosomes called?
cytogenetics
Answer: It is tightly packaged around proteins.
At what stage in a cell’s life can one se chromosomes (under a microscope).
During cell division.
Explain the difference between divergence and homology with regard to two DNA sequences.
Divergence is the fraction of differences observed, and homology is the fraction of identical sequence
What is phylogeny?
The graphical representation of evolutionary history of multiple lineages.
What do the nodes of a phylogeny represent?
Hypothetical ancestors.
Why is the genetic difference between humans and chimpanzees larger than 2%?
Each species has stretches of DNA that are missing in the other species.
Why do human genes not have more than two alleles for each locus in each individual?
Humans are diploid.
What is the problem with the classic definition of a gene as “a stretch of DNA that codes for a protein”?
Much of the non-protein coding genome also has functions: RNA genes and enhancers regulate gene expression
What is transcription factor (TF)?
A protein that influences the expression of one or more genes
Why is East Africa so rich in ancient human fossils?
the continental rift provides ideal conditions for fossilization.
Which continent exclusively contains hominid fossils older than 2 million years?
Africa
Which were the last two continents settled by ancient humans?
The Americas
Mention three extinct mammal species that had their ancient genomes
characterized ?
Neanderthal, Denisovan, Cave Bear.
How many different human-like species existed 50,000 years ago?
At least four.
What is the study of chromosomes called?
cytogenetics
