biology district assessment

number the steps in chronological order #1-4 ___ stem cells reproduce via mitosis ___ DNA from stem cells receives signals to turn on specific genes ___ the 1st cell (zygote) forms from sperm & egg ___ cells become specific cell type

(up > down) 2, 3, 1, 4

33. number the items in order from smallest to largest (#1-6) ___ cell ___ organ system ___ tissue ___ organism ___ organelle ___ organ

(up > down) 2, 5, 3, 6, 1, 4

CER: a mutation occurs that causes a dog's stomach enzymes (proteins) to digest food more slowly. describe how this could affect the dog

it will harm the dog because it will no longer be able to digest things as quickly as it needs to, which could lead to it being sick & malnourished

mitosis is used for growth & repair of an organism. explain how mitosis is important for each

mitosis allows an organism to grow & heal from injuries by dividing cells

what is the 1st step of protein synthesis? 2nd step?

transcription; translation

describe the meaning of cell differentiation

when a stem cell specializes to perform a specific function

every ___ (#) nitrogen bases/nucleotides codes for 1 amino acid

3

a giraffe nerve cell has 62 chromosomes. how many chromosomes are in a giraffes liver cell?

62 chromosomes

what is the result of transcription for this section of DNA: TGC ATT GCA

RNA: ACG UAA CGU

describe incomplete dominance

a blend where both alleles are partly expressed

what is a mutation? how can it affect the shape & function of the protein?

a change in the DNA sequence; changes how a cell looks & functions

what is the meaning of dominant allele?

allele is completely expressed

what is the meaning of recessive allele?

allele is not expressed in the presence of a dominant allele

what is a stem cell? why are they important for human development?

an unspecialized cell. they are able to divide & become specialized cells, which have a specific purpose

write 2-3 sentences comparing asexual & sexual reproduction. think about the genetic information thats passed down & whether it is identical or not to the parents

asexual reproduction requires 1 parent, while sexual reproduction requires 2. asexual reproduction creates offspring that is genetically identical to its single parent, while sexual reproduction allows offspring to inherit traits from both parents

choose the best answer: how can cells from the same organism have such different shapes & functions? a. during differentiation, different types of cells produce proteins which destroy the nonactive DNA, leading to cell specialization b. mutations in the cells' nuclei lead to new combinations of DNA, resulting in different shapes & functions in the different types of cells c. during differentiation, different parts of the DNA in each type of cell are activated, resulting in different structure & function of the cells

c

explain why cell differentiation relies on mitosis & not meiosis

cell differentiation is when a stem cell specializes to become a cell that can perform a specific function. meiosis is only responsible for the growth of sex cells, while mitosis is responsible for the division of unspecialized stem cells (that will later specialize)

what is the purpose of crossing over & why is it so important?

creates chromosomes that are different from the parent

how does sexual reproduction increase genetic variation in a species?

crossing-over, independent assortment

describe the structure of DNA

double helix

what types of cells does meiosis produce?

gametes (sex cells)

what is genetic variability?

genetic differences between parents & offspring

what are the pros & cons of genetic consistency?

pros: quick reproduction, requires only 1 parent for reproduction cons: cannot easily adapt to environmental changes

what are the pros & cons of genetic variability?

pros: slight differences, able to adapt to environmental changes cons: 2 parents needed for reproduction

human skin, muscle, blood, & nerve cells all contain the same number of chromosomes with the same genes. explain how these cells can perform specialized functions

some genes are activated & some are not depending on the needs of the cell

explain why DNA replication is an important part of cell division. what would happen without it?

the DNA in a cell must be copied in order for mitosis to occur at all. a cell that does not have enough chromosomes to divide will not divide

why is separation of the chromosomes so important? what could happen to the future baby if the chromosomes failed to separate properly?

the absence of the proper number of chromosomes can cause death or disability

how is the DNA of a giraffe different from that of a human?

the sequence of the bases are different

why do all of the cells in your body have the same DNA?

they all come from the same zygote