science unit A written Flashcards
Reproduction of a flower (male/female parts)
pollen (contains the male gametes of plant, found on the stamen)
ovules (contains the female gametes of plant, found in the pistil)
pollination (occurs when pollen is transferred from the stigma of the pistil -> fertilization)
Asexual reproduction and advantages and disadvantages
Involves only one parent. All of the offsprings results in the thing being identical to the parent.
Advantages- does not require any specialized cells, can produce quickly and build a large population quickly
Disadvantages - if conditions become unfavourable, the entire population may be wiped out.
sexual reproduction and advantages and disadvantages
Involves 2 individuals. The offspring will have a mix of characteristics (will be unique).
Advantage -provides a lot of variations
disadvantage - it takes a lot of time and energy and can only produce a limited amount of offspring.
process of sexual reproduction
Sperm cell penetrates egg cell -> the joining of the male and female gametes (which produces a zygote) -> cell division of the zygote (cleavage) takes place -> cell division continues -> a multicellular embryo develops
(it goes gametes, fertilization, zygote, embryo.)
2 benefits of a predator and prey relationship
predators reduce the size of the prey population which prevents the prey from outstripping their food supply (without predators the prey population would decrease more because of starvation). The predators tend to capture the old, sick or weak members of the prey which allows for more reproduction and a healthy offspring
list 3 types of interdependence among living things and provide examples
parasitism- where one organism is harmed and the other benefits (ex between a mosquito and a human)
commensalism - where one organism benefits and other is neutral (organism using tree for protection)
predator- prey relationship - consists of the interactions between two species and their consequent effects on each other. (ex between a fox and a rabbit)
Binary Fission, Budding, Spore production, Vegetative reproduction (examples of plant asexual reproduction)
Binary Fission: One celled organism split into two
Budding: a small bud or smaller version detaches and becomes a new individual
Spore production: the division of cells of the parent
Vegetative reproduction: no seed: cutting, tubers, bulbs and runners
What is DNA? (what it stands for, where it is found, who discovered it, what its composed of and how they combine)
DNA stands for Deoxyribonucleic acid- is the molecule that contains the genetic code of organisms found in the nucleus. DNA is in each cell in the organism and tells cells what proteins to make. Mostly, these proteins are enzymes. DNA is inherited by children from their parents. This is why children share traits with their parents, such as skin, hair and eye color. (acts as a blueprint)
Found in nucleoli- responsible for for storing information and passing it on
Scientist Oswald Avery discovered DNA, Watson and Crick discovered the structure of DNA
A DNA molecule is like a ladder, its composed of adenine, guanine, thymine, and cytosine. (A + T go together, G + C go together.
(A molecule that contains the genetic code of organisms found in the nucleus. Oswald Avery discovered this. Composed of Adenine, Guanine, Thymine, and Cytosine (A+ T go together, G +C). DNA is inherited by children from their parents like eye color, hair (Acts as a blueprint).)
Chromosomes (what they are, how many in humans, gametes)
To fit large amounts of DNA into their cells, its arranged into packages (chromosomes), it contains all the genes. Each human cell nucleus contains 46 chromosomes (we have a complete set of 46). Chromosomes are organized into pairs (we have 23 pairs)
(fits lots of DNA in cells and organizes it into packages and contains all the genes.)
Genes
Genes are responsible for the inheritance of an organisms characteristic features. a single gene is and uninterrupted segment of DNA.
-Genes are located on the chromosomes and come in pairs
(are responsible for the inheritance of an organisms characteristic features. located in packages)
Alleles
variation in the DNA sequence in genes, offsprings inherit genes from both parents. They are possible forms of the same genes and differ from one another in their exact DNA sequence.
(Dont memorize this, its just so that you understand: An allele is one of a pair of genes that appear at a particular location on a particular chromosome and control the same characteristic, such as blood type or color blindness. Alleles are also called alleleomorphs. Your blood type is determined by the alleles you inherited from your parents.) \
(brings out variation and genes from parents and differ from one allele to the other. could also be a possible form of a gene. Also is a form a gene may take that may affect a trait of an organism)
Mitosis- where it occurs, how many chromosomes are at the end of the process in humans, what this process is used for, how many times the cell divides (how many daughter cells are produced).
The process that produces two new cells with the same number of chromosomes is called mitosis. Its responsible for growth repair/regeneration. Mitosis occurs in the body cells of multicellular organisms. Once mitosis is complete, the cell has two groups of 46 chromosomes, each enclosed with their own nuclear membrane. The cell then splits in two by a process called cytokinesis, creating two clones of the original cell. (mitosis is 1 cell division).
(Occurs in growth and repair, # of chromosomes at the end of the process - 46, number of daughter cells produced - 2, used for growth and repair. Mitosis produces 2 offspring with the same number of chromosomes as the parent cell).
Meiosis- where it occurs, how many chromosomes are at the end of the process in humans, what this process is used for, how many times the cell divides (how many daughter cells are produced).
Meiosis is a type of cell division that produces cells with only half the DNA of a normal cell. Because each gamete has only half the DNA of a normal cell, when the male and female unite, the zygote has a complete set of DNA. Meiosis involves 2 cell divisions. Meiosis occurs in the sex cells, so the sperm and egg cells in the human body, to create even more of themselves.
On the other side, during meiosis I, same as mitosis, they are split into 2 cells, each of which has 46 chromosomes (46 sister chromatids in total). So, during meiosis II, these 2 cells was split again into 4 cells, each of which has 23 chromosomes (23 sister chromatids in total).
Meiosis is used in sex cells. Its goal is to make daughter cells with exactly half as many chromosomes as the starting cell.
(Occurs in sex cells, # of chromosomes at the end of the process - 23, number of daughter cells produced - 4, used for development of sex cells. Meiosis produces 4 sex cells and have half the number of chromosomes as the parent cell.)
Hybrid
Hybrid just means having a combination of two different alleles (the ‘letters’ meaning either dominant or recessive). The genotype of a hybrid wild have one capital letter and one lowercase letter, like “Bb”. The organism would still possess the dominant trait, like black hair in the cats in many of our textbook examples, but it would be able to pass on a recessive trait to it’s offspring.
A Hybrid trait is also called Heterozygous. (An organism produced by crossing 2 individual purebred for different forms of a trait).
Purebred
Purbred - a breeder who wishes to produce white cats should choose purepred parents (cats whose ancestors have produced only white offspring of several generations
