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1. What is a controlled experiment?
Controlled experiment– tests effect of a
single variable while keeping all other
variables the same
2. What is the difference between a hypothesis
and a theory?
hypothesis– a possible explanation to a scientific
question. (an “educated guess” based on prior knowledge and
observations)
Theory– a well tested and supported hypothesis
(Cell theory, theory of Natural Selection, Atomic
theory)
Observation classified into two types:
Quantitative– involve numbers, counting,
measuring objects.
Qualitative– involve characteristics that cannot
be easily measured or counted such as
color
or texture
3. When conducting experiments, sometimes the
results are not consistent and may yield results
that are obviously wrong. What might be some
typical sources of unavoidable errors?
•Human error (mistakes in conducting experiment)
•Small sample tested
•Contaminated sample
4. Why is the cell membrane referred to as being
semi-permeable?
Most membranes are selectively
permeable (some materials can pass
across membrane and others cannot) like
“sieve”
6. What is an enzyme and how does it speed up a
chemical reaction?
Enzymes– specialized proteins that act as
biological catalysts
(catalysts– a substance that speeds up rate of
chemical reaction by lowering a reactions
activation energy)
Enzymes are very specific
Name of enzyme derived
from reaction it catalyzes
Enzymes are not used up in a
chemical reaction.
7. What conditions affect the action of an enzyme
(name three things)
•Temperature
•pH
•Presence of substrate
14. Proteins are all made from amino acids. What
makes one protein different from another?
The number of amino acids and the sequence of
amino acids (like letters in an alphabet spelling
different words)
15. What effect does temperature have on
proteins?
It changes the 3-dimensional structure of the
protein (this will also change the way the protein
functions)
Like when you cook a steak or eggs- it changes
the consistency. It may also stop the action of an
enzyme- snake venom
17. What is mitosis and what types of cells
undergo mitosis?
Division of cells forming two identical new
daughter cells (body cells) 2n → 2n
Part of Cell Cycle
PMAT (stages)
followed by cytokinesis
18. What is the difference between diploid cells
and haploid cells?
Diploid (2n)- two sets of chromosomes (normal
number in body cells)
Haploid (n)- half the number of chromosomes
(found in sex cells-gametes)
19. What process produces diploid cells and
which produces haploid cells?
Mitosis- makes diploid cells 2n → 2n
Meiosis- makes haploid sex cells (gametes)
2n → n + n
20. What is meiosis and what does it result in?
Process of producing sex cells (gametes)
Results in four haploid (n) cells (sperm or egg)
21. Explain why this is a good representation of
fertilization: n + n =2n
Shows two haploid cells (gametes) coming
together to produce diploid (2n) cell-zygote
n + n =2n
22. What is meant be segregation when sex cells
(gametes) are produced?
22. What is meant be segregation when sex cells
(gametes) are produced?
Chromosomes segregate (separate) during
meiosis.
23. What is independent assortment?
Each of the chromosome
pairs separate
independently of the
others (like flipping a coin
each time to determine
which one to use)
24. What is a mutation?
Any change in an organisms DNA. Happens
naturally and randomly
25. Mutations may or may not affect the
expression of a gene. Why?
•It may not change the amino acid it codes for
(there are multiple combinations that code for
same amino acid)
•It may be a mutation in area of DNA that does not
code for proteins
26. What are sex chromosomes and what
combinations would result in a boy or a girl?
Girl = XX
Boy = XY
23rd pair of chromosomes
in humans